It's possible that you only have some traits and not a whole disorder. Or it's also possible to have two disorders at the same time. For example, AVPD is frequently found together with the DPD.

What I can't explain myself is how some psychiatrists treat us as if we were kids.
If you go to a hospital bc something is going bad, they make tests and then, give you a diagnosis. I also want to know what's going on in my head.

In relation to the therapy to follow, from what I know it is the same if you have social phobia or AvPD although the prognosis in the second case is not good.
But if you have BPD, some helpfull therapies are proven good results such as, dynamic therapy or mentalization.