How to deal with randomly scheduled shifts?

My biggest gripe at the moment is that my schedule can change ANY day regardless of what I do. I seriously can't plan anything until the day of a supposed empty day on my schedule.

I got called in to work to work on one of my off days and I got attitude for refusing originally. I get attitude for any of my choices with anyone above me and its really annoying.

Also, I got scheduled hours during my finals. wat2do about these random shifts or how I should be talking to the upper?

Man retail is a killer. I would rather work for Target for at least timing stability.

Last of my end rant, if someone wants time off for school who is a old worker, she is met with no attitude. But when I do it, I get crap for it and denied. Guess who got her shift, I did.