How do i prevent my hair from breaking?

i have been experiencing hair breakage for several months now. i tried changing shampoos but my hair's still breaking. i started noticing it when after i take a bath, there's A LOT of hair on the drain. now i'm using johnson's baby shampoo and stopped using conditioner. but there's still a lot of hair down the drain and when i comb afterwards. i'm really getting worried and i feel like my thick mane of hair is thinning. please help.