OCD is treatable by a range of therapies and typically responds well to drugs such as serotonin uptake inhibitors. If you stop being a Catholic and become, say, a Muslim, your OCD will continue but your obsessions will change to things like whether you have prayed properly five times a day or eaten non-halal food. If you become an atheist you will worry about things like harming others, or telling the truth, or food contamination. OCD is not a religious problem. All talking therapy is likely to be useful, including religious talking therapy. But a solution, where it is possible, requires diagnosis by a professional, treatment by a professional and ongoing support. If I were in your position I would begin by making an appointment with my ordinary doctor to whom I go for any health issue. I would explain the problem without going into the specific nature of the obsessions/compulsions/intrusive thoughts you experience except as required to explain the experience. The doctor, if properly informed about OCD, won’t care about what you obsess/have compulsions/experience intrusive thoughts about. Just that they happen. If one of the many options for standard medical treatment works for you you can then assess whether there was indeed a religious aspect to your experience and discuss that with your religious advisors. No everyone experiences long-term total success but few people do not experience some improvement with medical treatment. If you are a teenager the drugs I have mentioned may not be appropriate for you but a doctor can advise. For clarity I am not a Catholic or a believer.