I understand what you are going through. I have anti-Christian obsessional thoughts - have had them for ten years. I feel the guilt, anger, shame, and idea that God hates me sometimes too. I am sorry that you are having a hard time with OCD. I hope it helps to know that I do not hate you for what 'bad' thoughts you have against God. If I can forgive you and feel as much compassion for you as I do, then just imagine how much more God loves you, forgives you, and wants to help you. I know it is really hard to understand why this is happening, but just try not to be so hard on yourself. I truly believe that the thoughts we are afflicted with do not represent who we are, rather they reflect the structural/chemical problems we have in our brains.
On that note, if you have not done so, you might try a different medication. I am taking Prozac, which has helped quite a bit. Also, it usually takes pretty high dosages of med. to work for OCD. Don't give up, every day we live there is a chance and a hope. Find a good pyschiatrist and counselor if you have not done so already.
Good luck and God bless,
Chris