Really worried :/

I work in retail, and today I was working on the till. When I was counting the money with my manager at the end of my shift, she noticed the till I had been working on was £4.19 down. I feel really bad because I didn’t want her to assume that i took the money, because I didn’t, and she didn’t assume that anyway, but I still feel really bad :/ sometimes when I’m under pressure I might have given the wrong change out idk, but I really don’t want them to think that I took the money :/