Oh love, how horrible it is to feel like this. I posted something remarkably similar a few weeks ago. Everyone said it's really normal to feel like you are at this point in the treatment. You spoke about the bandicoots and it certainly sounds like you have a few loose in your house at the moment. The psychologist will help you chase them away; I'm so glad your appointment has finally come up. I find my psych to be so helpful.
So your words to me were "You WILL get through this, one step at a time". I know so well it's hard to know that when you're in the trenches like you are right now. So all the usual things: be kind to yourself, do something nice that you enjoy, take it hour by hour if necessary. A little exercise for the endorphins if you're feeling up for it. Plan something enjoyable for the future you can look forward to.
I hate the futility moods. Even though you're not a huggy person, I am (gotta be 20 seconds long to get that oxytocin release!) so I'm sending you a big bear one! You'll be OK, you'll be better than OK. Breathe, and dream of the beach next summer. Kate xox