Christians, How can I be forgiven for this addiction?

Hello, I am a firm Christian I don't doubt that god is real, I know he is real. But I have this Addiction coming from long before. Being a Teenager Peer pressure is always on me to do it. It seems like I can only break the addiction for maybe 2 days. Does God forgive me? I ask him to forgive me every time, but I'm not turning away from the sin for good, I just can't bring myself to do it. Its too hard for me to turn away, I once did for a week, but that was it... I truly feel horrible like I am hurting God, but its so hard for me to stop, is he merciful enough to forgive me knowing that I hate that I am addicted?