Bad Dream

I was really anxious about coming back to work last week after being sick & off work for 4 days. I'm not sure why. But the night before last I even had nightmares about it again. I dreamed that it was the first day of school and I woke up three hours late. Then I was in my classroom and there was trash everywhere, (no doubt my insecurities with being disorganized) the kids were running around, and my boss stopped by to tell me "not to be so mean to the kids."
It was awful. I just felt unprepared and anxious. I woke up nervous. Then I got to school and couldn't figure out why I felt that way. Everything was fine. I know what I am doing. It's weird. What the heck?