Abby,
I'm sorry things are so painful for you.
It sounds like you are working really hard in therapy and it is only natural that a lot of what is coming up in session is spilling out t othe rest of your week. It's really frustrating to have to deal with all of it without T's help but I think that is all a part of the process.
I really relate to wanting to skip therapy. I feel that way every week, yet I keep going every week. It is just painful and it sucks.
The only way out is through. If you get scared and run away, you will really only be prolonging your suffering.
So I want to encourage you to keep going, keep expressing yourself to T, even if it means having the 'tantrums' and expressing your frustration and anger at the process. That is part of the process.
And really try to take good care of yourself. Do whatever you can to use distractions and self-soothing when it gets to be too much to handle.
You will get through this.