Hair breaking of?

Idk what tf is going on with my hair… it’s been feeling flat, limp, not necessarily dry but frizzy, kinda feels greasy and brittle and everytime I touch it it feels weak and feel like it’s about to break or it is. Also excessive shedding. Idk if it’s moisture overload or protein overload bit something isn’t right. I do dust/trim my ends but I need some advice on what to do or what products to use