DID isn't a temporary thing, but it can "recede" in calmer times so that the symptoms are not so noticeable. In times of stress the symptoms (dissociation and switching) worsen.
Did you experience much trauma as a child or have attachment issues with your parents? DID can't suddenly appear in someone as an adult but it can "reappear" if it begins in early childhood, things are calm and well for a while and then you have major stresses (like you did in your 20s).