can someone tell me their worst mistake to make me feel better

so I was by myself down at the pro desk while it was super busy (phone ringing, people in line for phone sales while i already have customers on hold and orders that need to be paid for) and I’m working with this one customer who wants to order some doors. he wanted to hit $2500 for the bid room discount so he was just adding a bunch of stuff, I process the discount (around $500 off with his new total being around $2400) and we noticed one of the doors went up in price. I went to mark it down and take $44 off of the one door and ended up taking $44 off of everything. I didn’t notice because it was so busy and it didn’t ask me for a manager authorization. He put his card in and he paid and after it slowed down, I looked at the order again and noticed it said $920 in the discount section. $500 being from the bid room and $400 being from me and the remaining from preferred pricing. I know management is going to talk to me and I am actually horrified