Hair Loss

So I’ve had hair loss/thinning of hair since giving birth to my son a year ago. I thought it was possibly due to breastfeeding but I’ve slowed down breastfeeding a lot (only breastfeeding 4 times a day) and am going to stop soon. I’m getting really insecure about it and I have tried thickening shampoo/conditioner but it doesn’t work. I noticed when I was pregnant my hair was a little bit thicker and I definitely wasn’t balding. Should I start taking my prenatal vitamins again or should I take biotin? I just want something that will work. My prenatal vitamins were so expensive and biotin is much cheaper. Wondering if anybody has ever gone through this and has used biotin before.