Hair loss over the last 6 months..please read and help!

Okay..where to start? I'm 35, have always had a very healthy head of hair (lots of it, too). I took painkillers a good bit of a bad last year (but didn't really notice a great hair loss) which culminated in major back surgery in November 1999. Almost immediately thereafter, I started noticing large hair loss, which I put off to the anesthesia, etc. The problem is, here I am 6 months out, and the hair loss has not stopped. I was looking in the mirror last night, and was appalled. What sort of doctor should I consult about my hair loss? Endo? Dermatologist? Where do I start? I have grown my hair out to "cover" the loss, because it's curly, and the volume helps to hide the thinness. My ponytail now is the size of what used to be just a small handful of my hair. HELP!