Acute hair loss. Hair. please help me!

Sir/Mam, My hair started falling when I was in 1st year of engineering. I used to have dense long hair but then gradually I started keeping them sort to avoid hair loss but this didn't work and the problem continued. Whenever it started falling at a terrible rate I used to shave off my head and go bald. I shaved off my hair for around 8 times in 4 year. But now I'm in job this problem is not ending. My hair has become thin and my scalp is easily visible. Also I have noticed that my scalp is very prone to dandruff. I have tried my shampoos but none of them work even oils too..nothing work on the scalp and this dandruff starts itchiness and there starts hairfall. Please help me what should I do..I'm tired of this problem..I have tried my serums too but they suck.... I want to have hair..please help me