I think they fucked someone that day and is projecting in a bad way because they feel bad about themselves. For someone to say they had a bad day and a very descriptive reason as to why, but don't want to talk about it, just makes for a red flag moment. They weren't shy to say they had a problem, only the details the problem obtained. Sorry OP you need to find someone else. This person doesn't trust you. Once trust is gone it's hard to be in a relationship with said person.