I don't really look at my bipolar episodes as being personality changes, but rather energy changes and either leanings towards depression and maybe anxiety (and its symptoms) or high energy and either elation (and its symptoms) or a mix of high energy and irritable/angry/frustrated/anxious with perhaps some depressive symptoms. Mood changes are not personality changes. The closest to that, in my view would be if you have different alters, such as in DID (Dissociative Identity Disorder), which I highly doubt you have. And note that DID neither falls under the mood nor personality disorders umbrellas. It's not to say that different moods don't/can't make one act in ways that are out of the ordinary for them, but I think it's more sparked by the psychological pressures in the brain than actual change of personality (i.e. rare DID) or pattern of emotional responses that can become problematic (in a unique way, in some personality disorders). With all this said, many of these disorders have some symptoms in common that require expertise for differential diagnosis.

It's best if you discuss your situation with a therapist or psychiatrist so that they can help interpret what you're experiencing. Mood disorder, personality disorder, or something else.