Eriksplus,
Maybe the confusion stems from your use of the word alters, which would lead people to believe you have DID, when in fact that might not be the case.
Have you discussed with your therapist that you might be dealing with a different type of Dissociative Disorder? If they're saying you do not have DID and leaving it at that, then maybe you need to do some research on what does fit. That way you can finally be understood and properly diagnosed. I think you might feel a lot better with validation from a professional, and it might even help your own peace of mind.
Would something like the description I listed below fit? That might be the direction to head in if it does. If not, let us know and we'll keep trying to help you.