Needing advice please

Lately I've been feeling like I am possibly autistic or have ADD/ADHD. I've a whole other bunch of health issues ranging from joint/mobility issue to mental health issues. I was diagnosed 4 years ago with fibromyalgia and have been previously diagnosed as having bipolar and social anxiety disorder, due to the array of medical issues I have and my GP retiring, I'm scared to go to the new GP incase they think I'm being a hypochondriac as they don't know me or just don't take me seriously. My social anxiety also makes it hard for me to start a conversation face to face.

I'm looking for advice about how to open this conversation up with my gp, or if anyone can point me in the right direction of where I can possible get more information as everything I've read on NHS website says its pretty likely its not my bipolar that's the main reason i am how I am.