but I want to make sure this isn't just me.

If you apply for a job and then get it, and then between you accepting and you starting, the place where you're to be working decides to drastically change the job by taking the opportunity to unload onto you (as the new person) a load of work in the office other people don't want to do, it's not unreasonable for you (as the new person) to feel pissed off about this is it?