A bunch of girls stalking me?

So....... recently at my middle school, there were a bunch of girls just walking literally right behind me. I didn't notice for a while, and then I looked behind me. One of the girls said, "hey" in a shy voice. I turned my head forwards as I said, "Hey????" and walked away. Is this good? Bad? Am I somehow becoming extremely attractive to girls? Should I ask them what they were doing? CAN SOMEONE PLEASE TELL ME WHATS GOING ON!?