Lord, have mercy.
If you have a priest you trust and relate well to, you already have a big head start on your struggle! If you don't, sincerely ask God regularly from the bottom of your heart to help you find one: He will not let you down!
Here is my two cents worth of advice, I hope that at least some of it is relevant to you and that it helps: (And please remember, I am just a sinner like you, so what do I know. I'm just some guy on the internet. The main thing is to talk to you priest.)
Pray to the Lord to enter your life and for Him to heal you.
Please struggle to love yourself, and to accept God's love. You are God's creation and made in the image and likeness of God, and He loves you more than if you were His only child. This makes you worthy of love! Hate the sins you do, but not yourself. It's really tough being 16 and being in your situation. Just keep begging God in humility to help you. When you sin, just keep begging God to help you not to sin again. This is not easy, it is spiritual warfare. It is all too human to sin, but it can get much better through God's grace and your effort, believe me! Keep struggling to let the Lord work change in your life: struggle to let him do it, and not you. Ask your spiritual director about prayer, and ask the Holy Spirit to teach you how to pray. Struggle to devote a few minutes to silent prayer and/or recited prayer of some kind every day. (But ask your spiritual director (priest) about how to go about doing this, this is really important!) Drink a little Holy water every day. Go to communion (and confession) as much as possible: this is really important too! Get as much exercise as you can, and try to make it be in as natural a setting (forest, beach, riverbank, park, field etc.) as possible. Give thanks to God for everything good in your life, even if it seems really phony at first. Just keep being thankful.
You are in my unworthy prayers.