My sins are killing me

I feel like my sins are killing me. I can’t stop thinking about them, and it makes me feel like complete garbage. I used to watch 18+ stuff, and I don’t even know why, but I ended up watching gay 18+ too. It makes me feel so ashamed of myself, and I hate that I let it happen. I don’t even know how to talk to God after everything I’ve done. How am I supposed to ask for forgiveness when I’ve messed up this bad? I feel like I don’t deserve it, but at the same time, I really want to fix things. I just don’t know how to even start.