@TheGirlWhoReadsTooMuch I'm sorry to hear about how rough things have been for you. I can't give you a definitive roadmap since these are complicated and deeply personal things, but I'll try to help you by walking you through my story. You might relate to it in some ways.
It sounds like your belief in religion stems from fear of punishment, and that's a very damaging thing, trust me. Personally, I held onto my belief for so long because I was afraid of what would happen to me if I let go, but that didn't change the fact that nothing could change my past, and I wasn't making progress on myself no matter how hard I prayed or went to church. I had to contend with feelings and observations about my life being in conflict with what I was taught. I also had to trust myself when it came to realizing that the "god" I had in my mind was my own thoughts, and that asking it for help, or answers was futile. It felt good in a way, but it also felt like a loss because I had been using it as a coping mechanism to give me hope.
But when I think about it honestly, I also recognize that I tore myself down a lot by viewing my life in religious terms. For instance, I would make myself sound really helpless and pathetic while praying for forgiveness, and I would imagine a disdainful but dutiful, perfect god trying to fix me. What that did was pull me into a cycle, where I would keep doing things that made me feel bad, then I would hate on myself, and after, I would soothe the pain by imagining myself "fixed."
Similar to you, that's where a lot of my fears came from, and it's also where my mental compulsions came from. I wouldn't have had so much trouble with OCD if it weren't for these experiences. It kept me in its cycle by convincing me that leaving it was defeat or even doom while also offering me a chance to be redeemed. The thing is, I was never broken, and in fact, the only damage I had was self inflicted because I believed that I was. I don't want you to go through the same cycle. Yes it's difficult and scary to break away from it, but by doing so, you adjust your perspective of yourself and stop letting the cycle rule you.
Now, here's what I've learned about OCD that I think you should know.
First, understand that it's the result of your nervous system responding to triggers and then activating your brain. This is important for a few reasons. It means that your brain is essentially hijacked by the fear and can't process things normally. It also means that you won't find long term satisfaction by trying to ruminate. It's also the reason why OCD cannot be defeated with logic and reasoning.
Second, the only way to quell OCD is to not respond to it. Your nervous system needs to be given space to feel how it feels without you going into problem solving mode. This will help it deal with the sense of urgency and paralysis and over time it will recognize that there is no threat.
Third, remember that OCD wants you to do compulsions for its own feeling of security, but that every time you do compulsions, you are reinforcing to it that the fear is real and can only be dealt with through compulsions. Again, this is because it is driven by patterns and not reasoning.
Fourth, know that your OCD is going to keep trying to get you to engage. Even if you're making progress, it will try to give you feelings and reasons for why you should care about it again. It thinks it's doing what's best for you, but it's really just stressing itself (you) out for no reason.
Lastly, be patient and compassionate toward yourself. This is difficult and draining stuff to go through. You'll doubt yourself, you'll mess up, but progress isn't linear.
I truly believe you have what it takes to get through this, and I hope my writing gave you something valuable to use