Whom do I see to have hair loss assessed? Doctor? Nutritionist?

I'm relatively new to hair loss. I had a slightly receding hairline since I was a teenager, but it was nothing I worried about because it remained relatively the same through my early 20s as well. And other than the recessed part, my hair was really thick.

I figured it would continue to recess, but I thought it would be gradual. This past year it seems that the pace has picked up. It's recessed quite a bit. I can't lie, it's been quite traumatic. I look so different. I can't imagine getting accustomed to it, it just doesn't look good.

I've been reading a little bit about treatments like Propecia which might possibly prevent further hair-loss. I hope this works, and that I might combine this with a hair transplant to restore what I lost... but I'm unclear as to the probability of success.

I any case, who's the best person to see about this? To give me an assessment of what I should do in my specific case? My doctor? A nutritionist? Are there hair doctors? I don't know where to go...

Any help would be MUCH, MUCH appreciated.

Joe