Isha, don't let haters stop you. It sucks that happened to you, and I'm glad no one got hurt. But these types of things happen sometimes. I bet it wouldn't happen again - there are assholes like that out there, but most people aren't like that.
If anything gave you away, it was probably your nervousness. Walk into a place like you own it - it helps.
I think you handled em pretty well, but you might have considered calling the police, you weren't doing anything wrong, but they surely were.
