Hi devox!
It's important to ... tell him everything.. even though it may feel scary to do that. Go with no expectations except to just relax and let it happen. Be as honest as you can be, and backtrack if you find you have not been fully honest.... adding to something you've already said.
Being as open and honest as you can be will make all the difference. Remember, he is a professional who has likely heard everything and can accept anything and everything you have to say.
He is not there because he wants to judge; he is there because he cares deeply about people and has chosen to help people as his life's work. You will be in good, safe hands there.
You could plan something nice for yourself for after your appointment so you have something to look forward to beyond your appointment time. I have done this; I usually choose small rewards like having some of my favorite flavored tea or coffee and a good book, movie, or magazine at home waiting for me. This is your day to be good to you!
ECHOES