I've had hair loss for over 10 years now. I was on Asacol when it started. I used to have very, very thick hair and it fell out in clumps for months and months - even a year later it was still falling out. I switched to Colazal (Balsalazide) and it got a little better. All the mesalamine-based drugs can cause hair loss after long-term loss. It does stop eventually though.
Now I have very thin, fine hair - its never grown back to the thickness it once was. I'm trying to get off Prednisone and that has caused my hair to fall out again a ton. It's so thin now I can't stand to look at it! I know it will grow back once I'm completely off the Prednisone - for me its tapering the Prednisone that is causing it to fall out. I have seriously low DHEA levels - a little from birth control pills but mostly low from Prednisone. I started taking a DHEA supplement and that has helped me a little. So you may want to get that checked out. I take Yasmin as my birth control pill also as it specifically has the hormone dropsironone, which is in the family of spironactolone - a drug they give for hair loss sometimes.
As far as what else I've learned over the past 10 years, seeing dermatologists and endocrinologists - have your zinc, iron, vitamin D, ferritin, folic acid levels all tested. Low levels of those can cause hair loss.
For supplements I take Biotin, Calcium, Zinc (I had low zinc at one point), Vitamin C (helps body absorb zinc), L-lysine (known to help hair growth) and a multivitamin.
I know its hard not to stress about it but try if you can - stress can just make it worse. I have lots of little hairs growing back in now so hang in there. You may not have the same hair you had before, but it won't all fall out and you will get regrowth.