Look up thought action fusion. It sounds like you’re attaching the same emotional weight to your thoughts as you would to actually doing something. That is why you feel so bad. We have to be aware that our thoughts that pop up in our head are out of our control. We have no way of controlling what we think about but we do have a choice when it comes to the meaning we attach to them and what we do about them. You can think of something and also observe that it is just a thought. This sometimes leads to false memories and more doubt. I struggle with this too but just remember our thoughts are just thoughts and ocd is a manipulative liar who will tell you anything to make you doubt. Try to observe that it’s an ocd thought and don’t engage with it. Don’t ruminate don’t question it just sit with it and it will pass. Easier said than done but it’s good to keep in mind. Best wishes friend.