Does God still want me after I've denied Him by my sins?

Look at the life Christ had with the apostles. When they asked him dumb questions, he didn't belittle them or make them feel small. He was so real and present with them that they didn't fully comprehend he was the one who created the universe. The disciples felt so comfortable with him that John the Theologian laid his head on the breast of Christ at the Last Supper.

This is the same Christ who has a relationship with us. When Peter said with all his gusto, even if everyone denies you, I will not deny you, Christ didn't say, after you deny me I want nothing to do with you. He told him, you're going to deny me. Peter denied him, wept with bitter tears, and Christ restored him as an apostle, the very one who denied him, and Peter went out and worked great miracles in the Book of Acts.

People look at Judas and say he was cast off. No: Judas could have repented and returned to his role as an apostle, but he died in his misery and self-loathing. Christ doesn't need us, but never mistake that: he loves us intently and desires to be united with us. Yes, we fall, we make mistakes, and sometimes we fall back into old sins we wish we were done with.

That does not change who Christ is. As St Paul says, nothing can separate us from that love. Our relationship with him is predicated on his goodness, not our goodness. So when we begin to sink like Peter on the waves, we cry out to Christ and he pulls us out. Don't turn your attention to your sin. Always turn the eyes of your heart to Christ and ask for his help, his love, his mercy.