On my way to work today, I slowed at a stop sign and heard, maybe even felt, a "thunk" like something had hit my car. Sounded or felt like a ball or bird or something. Not like a rock. I got out and checked the side of the car, and saw nothing. A mile or so later, stopped at a red light in traffic and same thing. Seemed like it was coming from the driver side door. I thought maybe the doorhandles presenting, but doubt they would be that loud. Any ideas? it was enough to startle me. I really thought something had hit the car.