I want to know my rights in the work place?

Well what happened is that i was on the schedule to work this coming Tuesday and they took it away from me so they could add a new guy. i don't think that is right that that the did that to me. i think they should have waited till the following week to do that. I want to know if they are allowed to do that and what should i do? I work for Winn Dixie Supermarkets.