so what causes the yellowness and why does it curl under itself like that. Also why do some of my leaves die!?
Looks light heat stress either too hot of room or too close too lights. Could also be nute burn or your soil is too hot.
No need to repost. Not heat stress, or "too close to lights." Not nutrient burn, not hot soil. What you are seeing is known as Epinasty. That is the downward curling of leaves. There can be several causes for Epinasty and it looks to me like your plant has more than one issue. A full plant photo would be extremely useful but I can try to do without it. Firstly, the downward curl of your leaf as due to Epinasty is a result of your root zone not having access to enough oxygen. This could be due to a "muddy" soil mix without enough aeration material. This could also be due to a warm nutrient solution, as anything over 72 degrees is going to hold considerably less dissolved oxygen than the ideal temperatures of around 62 to 68 degrees for your water. Another cause of "Eagle Claw" is Nitrogen toxicity. This is commonly associated with a Phosphorus deficiency and can be recognized by a blueish hue to the leaves. I do not think you have a Nitrogen toxicity issue although I also cannot rule it out completely. Something I can recognize on your lower leaves is a Phosphorus deficiency. This is that crispy green, kinda moldy looking, damage to your leaves. The most common source of this issue is actually allowing the media to completely dry out which allows the Phosphorus to drop out of solution and precipitate with an available cation (like Calcium) to make a salt. This will lock out elements and your plant won't get what she needs. Also, during periods of greater root growth the plant may require additional phosphorus, especially post transplant later in vegetative growth. I think that your course of action here is to start with your water. Ensure the temperature is appropriate and that you are using a proper watering schedule. If the water is good then I would suggest flushing to remove excess Nitrogen and then using a balanced compost tea (1 gallon water with 1/2 cup worm castings, or forest humus, or cow manure compost, with 1 tablespoon of Molasses, brewed with an air stone for at least 12 hours). The compost tea will rebuild your microbial population in the soil, helping balance the pH, and assist in breaking down the dirt to make elements available for the plant for uptake. The mild nutritional charge should also provide a boost to the plant. If the problem spreads after rinsing and adding the tea then you probably have a bad soil mix and needed to amend it differently before using. Next time around I'd suggest a little extra high PK guano and at least 25% of the final mix to be perlite for indoor growing. With regards to the lower most leaves dying. That's kinda what they do. If they are far from the light source then the plant reapportions the nutrients it contains to better focus it's efforts in the areas that are properly lit up. This is a natural process and does not indicate any one particular issue other than inadequate lighting for the size of your plant.