Dustin, I am so sorry. When I was 17 and seeing a T the same thing happened to me. We worked out an out-of-pocket fee. My parents split it with me. There are ways to work though this. The first thing you need to do is just call your T (which I think you mentioned you did already) and try to work this out with her. There are some instances in which a request for more visits can be made. I know that happened once in my case. Again, there are ways in which this can be worked out. Suppose her out-of-pocket fee is too expensive or she is not flexible enough for it to affordable-- maybe you can see her every other week until you can get more visits. It will renew in 2008, right? That's not so far away. See if you can make it work until then. Anytime you want to talk, I am here for you.
BTW: My situation was identical to yours-- I also was not aware that I ran out of visits until way after the fact. I ended up owing a rather large sum of money. My T at the time was very flexible about this and I gave her a small portion of balance each week until it was paid off.