It sounds like it could be a dissociative disorder, but there are several of those and DID is just one of them. You could think of them as being on a spectrum of sorts from the normal dissociation that everyone has from time to time (the occasional spacing out), to distinct DID, with lots of variations in between.

These would tend to be more common in someone who had had some awful things happen to them in childhood, although you may not feel that was the case for you. Is it possible for you to see a therapist?