Usually in the summer it's a low season so we all take turns to travel. One coworker is going on vacation and she notified me that I will be working the full time and no days off (our day offs are different) because I need to cover her. Her day off is a day where we actually aren't officially open. I told her it doesn't make sense that I will be working for 10 hours a day for 20 days straight and coming on a day that doesn't serve but she stated that it's normal and everywhere is like that. Please advise what to do and how to handle this situation.