I have a hard time communicating and getting what I want to say out of my head and into my voice. I find that writing things down before going to the doc's helps a lot! Also this way I don't forget questions that I want to ask - because just getting there to the doctor's appointment I have such a panic attack that I forget everthing I wanted to discuss. So I keep a notebook, when I have a question I write it down so that I have it for my next appointment. It took about four tries before I found a doctor/pyschiatrist that I really like and clicked with. I'm so lucky to have found him - he really understands me!
So don't give up - keep trying - there is a doctor out there for you!