How Can I Draw Near to Allah Again?

I've committed so many sins-truly major ones-that I feel like I'm a terrible person. I became numb to wrongdoing, and sin just became normal in my life. I still remember when I was a kid, I'd turn to Allah for everything. But over time, I drifted away, and now I've lost my peace and stability. I'm in my late twenties, and I have heart issues, thyroid problems, liver and kidney concerns-nothing feels right in me. I've even thought about ending it, but I know that's haram and I won't do it; I don't want to hurt my parents. I just want to be normal again and to be closer to Allah. But sometimes I think I don't deserve His forgiveness because I'm only turning to Him when I need help. When I was young and full of energy, I hardly remembered Him. Now, with health troubles and life crises, I suddenly seek His mercy and support. It feels selfish.