Autism isn't one thing that you have or don't have, really; it's more of a continuum. Maybe you have really strong special interests (that's what they call them in the autism community--like hobbies, but all-consuming), but you don't have a lot of other traits. If it only happens when you're hypomanic/manic, maybe that's part of it; a reasonable assumption to make. But if it's constant, present even when you're in balance, it could be totally unrelated.

How attached to labels is your psychologist? Do you really need another label to address this? Would he be willing to work with you on learning moderation, so that your special interests do not interfere with your responsibilities? By this I mean moderation for YOU--not striving toward the typical, because typical is not the same thing as ideal. Special interests can get very intense, because they serve so many purposes--relaxation, engaging your mind, even as a bridge to people with similar interests.