Hey
Intrusive thoughts concerning religious matters can be very troublesome, but they are also very common with OCD. In fact, its you and millions of others that suffer with this particular problem.
A lot of people who get these religious thoughts are actually very conscientious about God/their religion or whatever, and would never ever agree with them. Unfortunately, OCD picks on your worst fears and the things you care most about. I used to get intrusive thoughts about God (some real horrible ones) when I was a lot younger, and like you, I felt guilty and like I had to do something to ward them off otherwise God would be displeased. Fortunately they passed.
Fear not though, God, if he is out there, knows when somebody is suffering from OCD and when someone is just being a jerk. After all, he's God.