You ARE a child of God, you are a SON. You need to give it to him, give your heart to him. Everytime you feel tempted, tell a friend or accountability partner, that you feel like falling into said temptation. Call them, pray that God takes these urges away and use SCRIPTURE against it. Jesus used scripture against the devil when he was tempted. The fact you feel guilty and bad for commiting those sins just shows the Holy Spirit is in you. But the more you do that sin the bigger wall you build. I'd advise to fast, get a good community around you, learn, grow, pray. Heck even text me on here when you're tempted and I'll do my best to help you if I can in time brother. Also try and look at the series of this matter. Jesus said Adulterers will NOT inherit the kingdom of God. Jesus also says if we look at a women lustfully, we have committed adultery. Be WATCHFUL. It says to take EVERY thought captive!! meaning you need to SPEAK and SAY "I TAKE this thought CAPTIVE and give it to you LORD!!" Because if you DWELL on that thought, you have already lost the battle pretty much. The tongue brings life and death, say that WHO THE SON SETS FREE, IS FREE INDEED. SPEAK IT!! When you come into agreement with that from your mouth, in the spirit realm things happen, you will change. Same thing as if you were to come into agreement with something bad with your tongue. For say like if you say "My head hurts" or "I have depression" You are coming into agreement with that and giving the enemy a tool against you. So speak that you are free, renounce and repent. BIND it. Much love brother, have a good day.