Hair Loss Doctors

I noticed hair on top of my thinning scalp and went to a dermatologist. She took a quick look (about 3 seconds) and told me that my options are Propecia and Rogaine. I spoke later with my aunt who is a pharmacist and she told me to keep on taking Propecia Rogaine can try first.but that my hair loss can be caused by stress, vitamin deficiency or thyroid problem. Dermatologist did not mention, or whether they these.is there a reason? I know that my aunt is not a doctor, but it's not like she knows nothing about subject.Should I make an appointment with my doctor and see what he says? I'm only 22 so I want to keep my hair a little longer while haha HELP!