My hair falls out

Im only 19 years old but ever since about a year ago, my hair has been thinning and falling out, a lot!! And I mean a lot, I even noticed some bald spots which I desperately try to conceal but everytime my hair loss gets worse  It gets harder to hide now!

People used to compliment my hair all the time, on how beautiful and long it was, and I loved it, but now it's just flat, thin, and my scalp doesn't look healthy, it's kind of red and sometimes I notice flakes and other times its very itchy. I eat very well, if anything I eat too much, and I take vitamins, so Im sure diet isnt the problem. I've tried shampoos that promise to reduce hair loss but they don't work. I told my doctor about it a bit, but she just said to take some vitamins, she really didn't think it was a problem. And I cant go to a dermatologist because I need a physician's referral, but my physician doesn't think its a big deal! She didn't even inspect my hair or head, when I told her my hair started falling out a lot she just told me to take vitamins and thats it. And I'm kind of emberrassed to tell her again and insist too much.  Besides a dermatologist what other kind of doctor can I go to