We've had an employee leave and my manager has basically dumped all the work he does on me. I've let him know that I am not in the right frame of mind to pick it up and that the work is of an additional resource which is being dumped on me.

He completely dismissed my mental state and mentioned they're not hiring and that there's no other option than to leverage me to the other team.

I told him what my stance is on this whole situation and if they still want to dump the work on me, there's nothing I can do.

We had a call today where he mentioned I'll be taking the new work and part of my existing work will be distributed. Tbh, I'm not really interested in their work since it's not my expertise and not something that interests me. I don't see myself putting in my best to get tasks completed and this is demotivating me af!

My training is to begin shortly and I want to know if there's anything I can do to get out of this situation right now. It probably is too late though.