I Think I'm Going to be Ill

I'm extremely nervous about work tonight. I don't even want to go. It's not because I don't like it. It's because I'm afraid I'm going to mess up on register. I did register all last week, but it was BREAKFAST. completely different set of buttons to push and combinations to find. I'm terrified no one will be there to watch me because I've already been working, and I'll have to wait for someone to come over and show me what to do like I had to the one day I worked a little over last week. I don't want to mess up! I don't want to get into any trouble for messing up! ;_; Please, please, please let someone be helping me today. I can't do lunch register alone. I'm so nervous about it that my stomach is in knots, and I feel like I'm going to be physically ill. Help.