pyramid of succ

First of all I'm not sure what I am going through. What happens to me is my mind wonders and I start thinking sick things about people I love and about God. I am a christian and attend church regurally. I love God and all these people I think sick things about. These thoughts are very perverted and once it enters my mind I can't get rid of it. I have kept this to myself because I am ashamed to tell someone what I think. I turely am a good person and try everyday to do what is right. I'm not like this 24/7 but these thoughts are in my brain and when I do obsess on them they ruin my day. I get nervous and I don't know what to do. Today I was with people all day and kept my mind focused on other things but as soon as I had idle time these thoughts started haunting me again. They make my stomach feel of knots. I can force myself to go through the day and not let on to anyone about this. It is killing me inside though. Know I don't have thoughts of wanting to hurt myself or anybody I just want to get rid of these thoughts and get back to normal thinking. I think how horrible I must be to have these thoughts and what others would think of me if they knew. I usually think that I am the only person in the world that has something like this happening to them. It is embarassing and unrelgious like to have these kind of thoughts. I am not afraid to admit to someone I have mind problems and need help. But I will have a hard time revealing to someone what is causing me to feel like I do. If anybody has a suggestion of where to start at I would really appreciate.