Paranoid or Panic?

So I walk out of the building after work yesterday, and I see a silver car with a guy wearing a hat sitting in the driver's seat. Mind you, by this time the parking lot is pretty much empty, so he's in plain sight.

As near my car, I hear the silver car start up.

Okay, I think. Creepy, but not suspicious. Even though I can feel someone watching me.

I sit in my car for a little while and make some calls and check my messages. The silver car is still running, but doesn't move while I do this.

So I go on my way and run to the nearest mall to do some shopping. And when I get out...

The silver car is parked two stalls away from mine.

Please tell me that I'm just being paranoid and there's really nothing to worry about...