I have never done but one time I woke up orgasming I guess I must have had a sleep sex dream and orgasmic in it. To be honest your story reminds me of a documentary I watched about sexinsomnia it is about people who have sex in their sleep and they don't even know that there doing it. It was quite baffling to me how someone could be asleep and manage to find someone and bone them and then have no memory of it. If I were you I'd talk to a doctor, a psychologist or even a neurologist to find out how this has been happening. Nothing to be ashamed of and I don't want to come across that I am trying to punish you for something you have no control of but knowing why or how it happens might help your anxiety around it.