"Commit your works to the Lord and your thoughts will be established."
The battle is the Lord's and He already won it on the Cross. Lust isn't a sin. But lust can lead us away from looking to Jesus. The only way I know out of every temptation is saying NO to myself and running to the Lord.
I could not overcome alcoholism even as a Christian. I was so ashamed! I finally came to the conclusion I had no power over it. I cried out to Jesus in brokenness and admitted nothing I did was keeping me from drinking. I just gave up. I followed along with Jesus like a crippled, messed-up failure of a Christian. But I followed Him.
One day as I was walking out of the grocery store (which sold alcohol) I stopped in my tracks right outside the doors. I all of a sudden realized that I hadn't even glanced at the aisles of booze. I couldn't believe it! It was amazing!!! I was like, "Oh my God, You have kept me from sin!!!!" It was the first time I didn't even have to battle the temptation!!!! It was not even a fight, I just wasn't thinking about it!!! It was a miracle of the Lord's grace. For me!!! He loved me and was faithful to deliver me!!!
All I can tell you is talk to Jesus. Tell Him everything in your heart. Trust Him to make a way of escape and He will do it. Just for you. Because He loves you and is faithful. He will renew your mind and give you right thoughts.
And don't condemn yourself. This is your personal walk with Jesus and He will make it a glorious walk. He will make you a living testimony to others.
Thank you for coming here and sharing your heart, young brother. I thank the Lord for bringing you to this point in the road and teaching you to seek Him out and learn of Him. I pray you continue to listen to Him and find the joy of His grace and liberty.
Blessings to you!