East17, when I started schema therapy we spent a while (I think about a month initially) working on ways of calming down, self soothing, managing emotions etc. Otherwise you are right, it would seem that you would open up all these potentially overwhelming emotions and then be left hanging.
I also had out of session contact. It's a shame your T can't offer that.

Do you know how long you have for doing schema therapy? I wonder if your T has a limited number of sessions and so is kind of rushing into things. It doesn't seem like a good idea though because in the end of the day it needs to be helpful to you, not harmful to you!