Is my retic pregnant? She's behaving strangely

I don't know if dirtydingusus is still posting, but I would sure appreciate some advice about my python!

I have two remaining pythons (both 14 years old) (the smallest and my favourite, Tommy the Royal python, died suspiciously whilst being cared for last summer at a local pet shop, and my biggest, Samba the Reticulated python, also became very ill at that shop (after only 7 weeks there - I am still taking her to the vets for treatment some 9 months later!).

Anyway, Jed (the male African Rock python, about 15 ft long) and Samba (the female Retic, about 18 ft long) have lived together for 13.5 years in my care, and at Easter this year was the very first time they have been observed mating together!

I am not a snake expert, having only had three snakes for 13.5 years, but I know my snakes' behaviours pretty well, and I have graduated from feeding them by hand (when they were smaller and less imposing) to now using long tongs (forceps?) behind the tank door!

I handle them regularly and always wash them in the bath immediately after feeding them (I know it makes more sense not to move them - the food inside has less chance of puncturing innards with sharp claws or teeth, and they might still try to bite me in feeding mode, but I can't risk them biting each other in the tank afterwards, so we've come to an understanding over the years, and, providing I am careful with towel or newspaper to hide my body heat as I approach them just after feeding, they now know that being touched by me just after feeding means only one thing - a trip to the bath and back!)

Anyway, to the point - the Saturday before last, it had been a good three weeks since Samba ate (she was shedding, so wouldn't eat until then), and I have to admit, I may have caused her problem - normally Jed comes out of the tank into a smaller feeding tank, and Samba stays put so I feed her in the main tank (less risky that way round, because although he bites more readily, he always lets go immediately, sort of spits me out as if to say eewww, that wasn't tasty!, but she bites and hangs on for dear life! however, she has only bitten me twice in 13.5 years (not bad for a retic, with their snappy reputation!) and that was because I was stupid enough about 10 years ago to feed her by hand, and she smelled the rat and sensed the heat of my hand and bit me instead of the rat! so my fault totally, she's otherwise very placid and gentle, although very dartingly curious to investigate things, can be quite scary how quickly she rushes up to see what's what). Anyway, this time Jed was sleepy and stayed in the main tank, while she was hungry and came out of the tank, so, to avoid being accidentally bitten by an 18footer, I threw a rat in front of her and ducked down the stairs, and sure enough she started to eat it (defrosted only, never feed either of them live anymore), and, to make sure I didn't get into difficulties with the next 7 rats, I chain-fed them to her (i.e. one after the other, as her mouth opens to swallow the tail of the last rat, I insert the next one, and she thinks she is just eating one very long rat!!
I also accidentally spilled too much vitamin powder onto the rats' bodies, but the vet thinks that wouldn't have caused the next problem : the very next day she threw up 6 of the 8 rats!!
Smelly and starting to decompose already, the last couple! She's never ever done that before - maybe I fed her too many? But surely 8 medium rats for an 18ft snake is not too much? Or maybe one of the rats was starting to go bad, and if she had had the chance to refuse to eat it, she might have done, but because I forced them into her by chain-feeding, the only option she had was to sick them up?

However, my mum says it was her "morning sickness'! And also, the last two weeks, she has been extremely anxious to get out of the tank, so much so that she is actually causing her head to bleed and be dented, so hard is she pushing against the glass-retaining wood rods inside the tank door! (This is very unusual behaviour for her - normally she may try to get out by banging her head on the glass, but never before has she done that so hard that she has damaged her head - she must be desperate!)

On top of that, her gums have swollen horribly (but I now suspect that that is because she has been pushing too hard to get out of the tank, with her mouth against the glass, and she maybe has bruised her gums and that's why they have swollen?)
So the vet has given me some antibiotic injections (hey, I learned how to inject a snake this January, when her all-over-body lumps got scarily worse, a condition caused directly by being at this pet shop last summer (my brother moved in and hates my snakes - scared of them - I'm 5ft2" female and handle 6st monsters, while he is 6ft2", built like a brick shithouse, and startles every time they come up the back of his chair!! so he persuaded me it would be a good idea to find someone to look after all three for one year, until my brother was due to move out again! One dead snake and one very ill snake later, and I wish we had found another solution....))
and the vet also gave me a solution to pipette onto her gums directly, and some cream for her wounds on the top of her head.

The last two nights she has had me up most of the night, whilst she goes round and round my room - finally, extremely tired and wanting badly to sleep, I finally remembered my mum's view that she may be pregnant, and got a huge cardboard box out of the attic, cut out an entrance hole, and put it upside down inside the tank (on top of the heat mat) and sure enough, she went in there and slept the rest of the night! Blessed be!

Tonight she has again damaged her head trying to get out of the tank before I got home, so I let her roam around my room again (she managed to break my curtain pole!) while I fixed some padding around the glass-retaining wood rod that she hurts her head on in the tank!

Is she trying to make a nest? or burrow somewhere dark and cosy ready to lay eggs?

How long do pythons stay gravid, before laying their eggs?

If a rock python and a retic have mated, would the offspring survive, or be still-born (cross-breeds)?

Does anyone have any experience of breeding retics? Will she try to eat her young?

Will the babies automatically be snappy? (Not that keen at all to be bitten, but I guess it goes with the territory of being a snake step-mum!)

And, as heartbreaking as it might be to find them new homes, I could not keep 15-20 little monsters! Especially if not all of them have their mum's unusually kind temperament...
... so how much would they be worth? And how would I find suitable owners? I'm so fussy about my snakes' care - I get up at all hours of the night if I hear them banging on the glass with their noses, and change their bedding, and refill their water bowl at the slightest sign of dirt, and give them exercise up and down the stairs, and even use filtered water sometimes! And help them shed in the bath, if needed. And put them in the garden in summer.

As you can see, love them immensely!

Would love to hear back from other python lovers (well, that sounds sexually deviant, so I guess I mean other pythonophiles!).

Will try to post some photos - not so hot with the old techology (still can't program my video, but, hey, I'm a girl...! but I'll try to get pics of Samba & Jed on here, and departed Tommy too).