I feel the same, but I didn't "blame" it on several personalities, but two other things. I can't hide things from myself like normal people can. If I have a less pleasant thought, I know I have it. Everything in myself is so clearly visible to me. Also I dislike the conflict it makes having differing opinions for example, of the same thing, so my mind organized clusters of traits that actually match up.

These clusters I will sort of perceive as different personalities. I think it was how my mind resolved "normal" inner conflict since I cannot sweep it under the carpet. And in reality I don't really think we're just one person anyway. That is just a perception.

Look at those people who had their corpus callosum cut. Their right and left hand can have two different wills. So we all have this inside of us. We're probably even more fragmented than this, but something makes "us" work together as one. I think we're born without one solid self. And that it forms later in life.