hair problems

Hi, I just signed up on this site to know what exacly is going on with my hair. So since I was 15 I had a lot of baby Hair on my hairline but since mid October I started noticing a lot of hair loss/thinning where those baby hair are and I’d like to know: is this the first stage of hair loss, is...

When I took a picture of the back of my hair I noticed this Here are pictures on the front Left temple: Right temple (I feel like it has receded): Hairline: And my crown: I don't know what is going on the back of my hair is the most concerning. What do you guy think.