Marijuana and pain in stomach the next day

Ok so ive been only using weed. No other drugs ... I either use glass pipe or a zigzag ... I have notice for about a month now that when i smoke weed i get terrible pain in my stomach !! .. Why is that.. I read other threats but ppl sometime get off topic ... So does someone have a real explanation before i go to the doctor and think its something serious ?... Please help, weed relaxes me and id hate to quit it but if its something serious ill have to stick to mommy juice for now on fr. And happens on a gram or less lol i think haha im not sure how big or small grams are i dont care about all that i just know how much i can take and thats as big as ur wedding fingernail-idk if thats a gram but like i said dont care i just needed enough to relax me and away fom mommy life for a bit ( yes my husband is always here to watch our baby , i wouldnt never watch her when i get high)..haha .BUT ANYWAYS please let me know before i completely stop weed