Schedule Mix Up

Originally, I was scheduled to work tonight from 7pm to 7am. However, I called the nurse that does the scheduling about 1.5-2 weeks ago, and informed her that my schedule was changing due to school (the change more-in-less affected other days of the summer, not today,) and she said that was fine and we worked out a new schedule, and part of that new schedule was today's workday being moved up to tomorrow and a time change, so the 13th from 7a to 7p. Two weeks later, today, I get a phone call telling me that I was supposed to be at work at 7pm. Only the scheduling manager and I had clearly worked that out. The nurse that called tonight called the scheduling manager, and she said that I was scheduled for today that I wasn't needed tomorrow, even though her and I had determined that I was to work tomorrow from 7a to 7p. I'm thinking that she forgot to change the schedule and didn't want to admit to it. The nurse that called me tonight didn't really sound like it was too urgent for me to come in. She just said that the other CNAs would be behind. The problem is that I don't feel like coming in tonight and I have planed the past couple of sleep cycles around not having to work tonight, not to mention that I didn't have access to my car when the nurse called me. Anyway, I guess I won't be coming in tomorrow morning either.