Are you on blood thinners from the clot? That could be it. I had blood clots in my lungs and now from being on coumadin I'm noticing my hair's coming out...luckily I have a lot, so I'd have to lose quite a bit to notice, but...who wants their hair any thinner? Also, surgery (don't know if you've had any lately) can cause you to lose hair. I don't know about the prednisone though...maybe others will come along. I haven't taken prednisone for a long enough time to notice anything but leg aches and irritability.
Also, yes, your hair will grow back. If it's from meds or surgery or something like that, eventually it'll grow back in. It always seems like it takes forever, but it will!
31 yr old female-dx with Crohn's in '97 after emergency resection and appendectomy, 2nd resection '05, Bilateral pulmonary emboli 10/09
Currently on Humira, Omeprazole, Effexor, Seroquel, Calcium, Vit D, sublingual B12, Coumadin