As Restin said, any number of things may be holding up T's response. A phone call may be a better option... Also, you may want to have a conversation with T around how she respondes to self-injury, and what are her grounds for forcing hospitalization. Generally, if they are going to force you to go, they do it in the moment, and not wait for the next session. Most T's will only try to force you into going if they feel you are an immenant threat to yourself or others. That would mean that you are planning something in the immediate future, and that is why they feel the need to force their hand. The doctors I've seen that sent me involuntarily for self-injury have never let me leave the office. (also, it was always a nurse or doctor, and never a T, though I know some T's will respond that way)...
Chances are, she may have a hospital conversation with you, but that doesn't automatically mean she will send you there, just that she wants to assess your safety level.
Try to keep breathing and stick it out to see how things go with her next week. And feel free to come talk more about it.