Hunny, I'm so sorry that you're going through this. I'm also a Christian that suffers from OCD. My OCD has been recurring for the past 4 years and always comes back in different forms. I, too, suffered from nasty and violent thoughts that were totally disgusting and out of my character. To think of it, I really haven't had one of those thoughts in a while. But when I did, my clinician at my program encouraged me to make a list of affirmations to think about when I had a violent thought. Much like what RuralOwlUK said, one of my affirmations was like "This is not me thinking this thought; it's just my anxiety." She said it was a manifestation of all the anxious and obsessive/compulsive feelings that I had built up inside. Maybe you could try some meditation and whatnot to relax your mind and make you feel less anxious? & Divert your mind right away when you think those thoughts. Think about happy things and whatnot. Begin focusing on something else, don't allow your mind to even so much as ponder the thoughts.
For pretty much my entire 6th grade year, I had OCD regarding God and religion. I'd spend hours a day reading a Bible, bring a Bible with me everywhere I went, sit on the internet and read about God and Jesus for hours, and that's literally all I would talk about. It even got to the point my mom stopped bringing me to church, in attempt to lessen my obsession. & Sometimes I would have derogatory religious thoughts as well that concerned me. Just always remember that this isn't YOU; this is just your anxiety. Let the thoughts go. They are of zero importance. It's not you thinking these thoughts, it's not the devil trying to bring you down, it's just your anxiety acting up. You're a good person and you are not to blame for these thoughts.
I also believe that you could benefit from therapy. I'm really not much help in regards to expenses and whatnot considering I'm only 16 years old & my mom takes care of all that for me, but perhaps your insurance will pay for a good portion of your therapy? Look into the therapy options that go along with your insurance.