Can you envision the session being over? If so, how will you be feeling then?

If you expect to feel better in any sense (relieved, released, whatever), then you're expecting the session to go well. Maybe you can draw some strength & comfort from that. If you can believe it'll be worth it, perhaps a bit of the dread will lessen.

I've been there. Your posting has brought it all back. For me, it was well worth struggling thru--took me a few days to get it tho. I'll be thinking of you.