I have the same issue but its not from anything I did to my hair. I have type 3B hair and my crown is so thin. I was toppik which is a powder that covers the scalp so you only see a full head of hair. I put Indian oil 2x a week and use rogaine for men 5%.
Its annoying and I should not have to go through losing my hair at 30 but Im trying to find a solution to my issue. I also heard coconut oil, aloe vera gel and castor oil would help the situation as well.
Im hoping these things work and help my hair grow back. Any feedback or suggestions would be great.