Hi Misswimmy,
I've been following this whole thread, and a lot of your others. I'm sorry you're going through all this right now. I can empathize with what it's like to be your age in a very difficult family situation and not having support from them or many others to deal with strong emotional issues. I was in that place at 15, and to an extent my sister is as well.
I think you have a really good t. She seems very loving and like she does care from what you've written in the past. It does concern me that in this thread you said that she "backs off" when she sees you start to get upset, and then switches the subject. I know that with my former t, some of the best work was when she saw me upset, acknowledged it and got me to talk about what was going on! This was something I absolutely wouldn't have done had she not pushed it out of me in a loving way!
I understand what others have said about her not being able to be there for you through text and e-mail right when you need her between sessions. I really do think that this is something you two should talk about and make plans on, what you do when stuff like this happens. I understand too about the not going to school thing, especially if it has to do with your OCD, which you said was triggered by her comment.
But it really does worry me about her not addressing stuff in the moment in session, and not teaching you ways to deal with what's come up, or at the least using the relationship to help you calm down. Like helping you feel close enough to her in those moments to open up and have her be there for you, so you could have a model of someone doing that for once. I think too that you might benifit from talking with her about this, and clearly saying that you feel abandoned in those moments when you're upset and she backs off.
Sorry this is so long! I wish there was more I could say or do to help. Please keep posting.