I can’t make a diagnosis or confirm the diagnoses you have. But I do have two important suggestions.
First, see your medical doctor. You may be correct that the problems come from anxiety. But it’s also possible that the anxiety is caused by an undiagnosed medical problem. I’m especially concerned about your headaches.
Secondly, send a copy of your letter to me and this response to your therapist. Your letter is an eloquent description of how you are feeling. It will help your therapist understand what you are dealing with. Then make an appointment. The first thing to address is your anxiety about addressing anything. You can’t do useful therapeutic work if you are so anxious you can’t begin to talk about your distress.
I’m very glad you have a therapist to return to. Even if you only had one session, some things were said that can be built on. Please, please don’t quit if you get upset. The upset is exactly what you need most to be talking about. Working on it will help you get comfortable so that you can then work on the other issues.
I wish you well.