I want and need to quit pornography and masturbation. Please help me!

I started rubbing my ya know against table corners when I was young like in 3rd grade and I did that for a while in elementary. I didn’t know what porn was but when I found out it slowly became an addiction. I’ve done some terrible things online that haunt me to this day when I was a minor. Newly 18 now. I do it multiple times a day for hours on end. The content has gotten worse and worse and even worse. As soon as I finish I feel HORRIBLE. I don’t want to do this anymore. I hate myself for it I need to quit but I don’t know how. Twitter (x) has so much horrible stuff on there and it’s all really easy to find. Please give me any help you can. Thank you.