Mouse I did that too once in therapy. I felt this overwhelming urge to NOT be there-- the session had only gone on for 20 minutes, and I told the T., "I really feel I don't want to be here". To which he replied, "Well, I can't make you stay, if you want to leave you can go"......
This was a difficult place for me to be in, as I very rarely acted on my feelings-- hold them in, is what I do. So, I did it-- I left!

couldn't believe I was doing that! it felt like an accomplishment and yet at the same time-- oddly enough-- I felt rejected...

was so confused....
It is scary for me to feel I may "need" someone-- as that somehow feels like they then have the power... like it's their move now.... feels vulnerable.
I hope you and your T. will come to an understanding as to what it was all about and then that leads to better understanding yourself in relation to others.
mouse-
mandy