I have a manager who does something similar; if you ask for a week off, she doesn't schedule you the week after that either. It sucks, especially if you need the money, but at least you won't have to work under that kind of management much longer.
Same thing happened to me with my last job. Luckily I was giving my two weeks due to the fact that I got another job though so I didn't need the last shifts. Looking at your username I'm assuming you're not in dire need of those last shifts either so that's good.