Confused

I have ongoing issues with dissociation - my depersonalization/derealization is fairly solid, so I'm not too concerned with it. However, it's the identity aspect I really have an issue with. Most of the time, I'm fine. Just me. But then other times, I'm so obviously a different person. Once I go back to being myself, though, I write it off as a mood and tell myself I'm a fake. I'm worried I just have extreme mood changes and really don't change in personality even though there have been several times where it's happened. I've experienced physical effects because of it too, but I can't seem to convince myself it's something I should tell my psychiatrist to see what he says out of fear of it just being a mood.
It not being consistent at all doesn't help.

Well whether or not you should go see a therapist really depends on whether or not it is bothering you, dissociation is fairly normal and when I have told people who are singletons that I have multiples they often say that they sometimes show different sides of themselves in different situations. So, if you are experiencing a consistency in situational responses this would be within the realms of normal. Usually my alters will respond differently to me in the same situations, because they don't think the way I do. For instance If I encountered someone who was being aggressive to us our responses would range from abject aggression, fear, laughing in their face and talking calmly with them depending on the alter involved.

If you are already seeing therapist for the dissociation and depersonalization then I would definitely mention the experience to them and see what they think it is. If not I would weigh up how well you are coping and decide if therapy is right for you now. But I would say, don't leave it till it starts overwhelming you, it is easier to fix that way.