Now I take my phone even to the bathroom, and as soon as I get home and lie down, I start scrolling through videos and social media, absorbing tons of fragmented information until I feel dizzy. Why can’t I stop doing something that I know is harmful and doesn’t even make me feel happy?
Because you don't have other things to do or you might be lazy to do other things.
You need to create a hobby that would keep you off from your mobile phone.
Why not try exercising or any sort of physical activities like sports.