M25: I am losing hair like crazy. ( Please read body text, and guide me)

I have dandruff from past 15 years, although I didn't cared much. I think I have some fungal dandruff, when the last time I got bald there were layers dandruff and it turned pink/purple when barber scraped with razor. Now I want to know how to fix this hair fall and should I get a zero cut to reduce hair fall. Thank you