It's never happened to me.
Perhaps that person is talking to someone on his cell phone and just happens to be glancing at you. i.e., he isn't talking about you at all.
*sniff* I wish I had friends.. or even people who pretended to be my friend.
reminds me of Donnie Brasco. Al Pacino says, "If I introduce you as 'A friend of mine' it means you're an alright guy. If I introduce you as 'A friend of ours,' it means you're a made man."