There is no sin that is to big for God to wash a way. no matter how messed up you are feeling, just go on your knees and call out to the One that is able to take u away from this mess and turn you into one of his precious jewels, because that is what you truly are. Ask for forgiveness and just start walking the walk, because He wants you and He loves YOU. God will grant you strength and is able to deliver you from every addiction. May The lord Jesus Christ cover you with his blood and protect you from harm.
Find a method that would help you not to look at those sexual stuff,, like maybe putting a parenting protection on your computer, I know it is also very easy to take it off. But what I always read is Galatians 5: 20. Stick to this scripture. It helps allot. And even if you watched that which is sexual once again, just ask God to forgive you (without making it a game)
He will help you and I will be praying for you.
I hope this made a differance for you.
May God bless you with his define healing, strength and a repented heart