From someone else who dealt with serious anxiety/discomfort/zoning out during therapy, I think you just have to go at your own pace. If you are self-motivated and already feel like you're pushing yourself to move forward/share more, then you are probably already doing what you should be.

It took me almost a year of therapy before I stopped getting a sick stomach/tons of anxiety before every single session. But, I can say, now I really don't get that any more. I don't really zone out too much any more either, though I still forget things if I have a really hard session. Little steps forward so that you get used to sharing/connecting, and over time you will learn that it's OK and your body will learn not to have such an extreme anxiety response. That's my opinion at least.

I also do a lot of sharing outside of session via email. This has pros and cons. The con is that if I overshare that way, there can be a lot of anxiety build up before seeing her face-to-face and getting some reassurance. But overall, the email helps me share in a lower stress format, and then I already know she knows it, so after I settle down, I can revisit it in session without it being too scary.

Also, my T suggested relaxation exercises once, and though I didn't follow up on those, that might be another option for taming the anxiety too?

I also try to write out everything I remember directly after session. That helps me not forget more things and gives me a chance to think about what we discussed and email additional things I wanted to respond but didn't get to during session.

It sounds like you're motivated to share more and so, if your experience is anything like mine, it will just mean taking lots of baby steps forward and eventually it will get easier.