The guilt that you feel is just another form of anxiety. When our minds are idle, anxiety will naturally find something for us to worry about. I have also experienced the guilty feeling that you described. You are not crazy, you are far from it. In fact, anxiety only happens to people with high functioning brains, which means that you are probably a smartypants :) If you feel guilty about what you do, try telling someone. I find that it helps me and gives me a feeling that I have gotten something off my chest. Even just saying it out loud can help you rationalize things. Best wishes!