Dear redcar:
Your fears: getting second strike, having one to go before getting fired. And paying for strike two. Your job allows for three mistakes. Maybe the person/s counting the mistakes will make a mistake and not count this one. That will be their mistakes. Often enough I avoided consequences for my mistakes because others made mistakes (It is amazing how often others make mistakes!)
To err is human. It often causes anxiety to err. I am trying to REST a bit in the reality that mistakes are so very, very VERY common everywhere!
anita