I took money out of the donation box at church

Last year our church had a fundraiser for someone I knew growing up. The person was in a motorcycle accident and needed an expensive surgery. The decon at the church set up a donation box and asked me to collect money from people. The guy that we were collecting for has always been a bully in school. He use to pick on me and other children. I never liked him. I also was behind on my rent so when no one was looking I slipped out some money that ended up being a few hundred dollars. Now I feels so bad about it. I’ve prayed on it. Still it bothers me.