When I was younger my mom and everyone else was convinced I had OCD. And then many many years later I was given a proper evaluation and diagnosed with PDDNOS and at first it didn't mean anything to me. But as I learned more about it I found that a lot of what we thought were symptoms of OCD were misunderstood symptoms of PDDNOS.
And yes I have a VERY hard time with change. I have a schedule and if it's thrown off even in the slightest I get very disoriented. Before any big changes can happen I have to know about them months ahead of time so I can think on it and get used to the idea. This kind of just applies to me as an artist, but if I draw things from a different angle than usual I get really confused and disoriented.
I think what would be a good thing to do is ask why they think you have whichever disorder. And/or look up the symptoms yourself. Pick out which you think do and don't fit you then ask about the ones you think fit you most. A lot of people say self diagnosing is bad, but it's really helpful if your informed and know what to talk to a professional about.

Because in truth, I am that monster.
We are an awkward little system that obsesses over things. We are Sam, Beyond, Stacy, Kevin, Kitty, Shannon,Link, Peyita, Stephen, Nicole, Damon, Pumpkin, Illonor, Daran,LIly. Feel free to send random cute things.