sunvick,
Welcome to the forum.
I'm sorry your daughter is feeling so lousy, despite having good results on her colonoscopy.
Yes, IMO, it could very well the be drugs she is taking - they are well know to have lots of side effects. And in some, they are not well tolerated.
I could not tolerate the 5asa's very well - they gave me terrible stomach pains and liquid D.
I would recommend you see about switching her meds.
But more importantly, it would be great if you could do some research and get her on LDN - low dose naltrexone. It's been very effective in Crohns and UC, and has almost no side effects. If you are interested, I will post the links for it here for you.
Good luck and I hope she feels better soon.