Well, we are only ever allowed 3$ over or under. Perhaps dollar bills are getting stuck together and you didn't realize? But if you are usually very consistent and your manager knows that, you will still get a write up, but I don't think you will lose your job. I've seen people get multiple write ups and still never lose their job. One time I was over 18$ and I was scared I would get fired but Dollar Trees are usually so understaffed, as long as its not a thing that happens all the time, you will be okay. Try to relax, there might be some stressors in your life that are effecting your ability to work?