Talulah, how about just jotting down a few notes that can remind you of what you want to talk about once you are in the session? That way, you have your reminder in hand of what you want to discuss, and you don't have to send the long missives through insecure e-mail. I would be very nervous about that too.

My T does not give out his e-mail address. In a way, it's good, because I really like to write and have a harder time speaking. So his not letting me communicate by e-mail is just one way he forces me to be responsible for my own sessions. Sometimes I feel like, hey, he treats me like a grown-up! I have be a responsible adult and choose the topic on my own. It is still hard for me to start the sessions, but I do take pride in being able to do it each time. I usually have too much to talk about and having to choose helps me prioritize what is the most important topic at that moment. Sometimes I do an exercise at home the night before the session that goes like this. In one sentence or less, answer:
"If I could talk about only one thing to my therapist tomorrow, it would be....."

I try to get it down to just a phrase. No going on and on and on. This really helps me focus on what is most important to me to discuss.

I realize this may not work for everyone. We all work out our own little tricks.

ETA: thanks Talulah for the info on notetaking. I didn't realize they all had to do that.