I'm afraid I made a massive mistake
How did you end up making a mistake?
I was tired and then made a bad decision in a bad condition.
We all make mistakes in our lives. How you respond to the mistake is what determines the outcome.
I know you are right but I'm scared about the results.
As long as you are not hurting others, it can't be that bad. Do what you can, but do not over exert yourself trying to remedy the situation.