Hi, you may have already found an answer for this but I just thought that if you hadn't then this may help.
I'm 15, 16 in January, and I've always had thick hair but it has gone very thin.
I have PCOS which is what is causing it. I have a high level of testosterone and blah blah blah~ Anyway I get a lot of acne and a lot of hair on my body (like legs, arms, stomach) and it's very dark. My periods were also very irregular when I did have them.
I suggest going to the doctor so that they can help, it might be something it might not be but they are there to help but you need to think of other things to go with it, the main things for me were my periods and of course the hair, but since I'm a teen I was already on spot medication.
I hope I helped... or not...