Opinions wanted: Out-of-the-ordinary Nice? Or Out-of-the-ordinary Creepy?

I had a run-in with a fellow today, and I am stumped as to how to feel about it. So I am asking you, internet.

I had to run up to the grocery store right before we put Alex to bed because both Paul and I had forgotten that we were out of milk. Paul was on the phone and happened to be more exhausted than I was at this point (which NEVER happens anymore), so I grabbed my keys and ran up there. On my way out, I passed a younger gentleman who was coming into the store with a few other people (not sure if they were in the same group or not). Right when I passed him, I heard him say, 'CONGRATS!' I turned, and saw that he was still walking, but glancing back at me. Now, I can only assume that he meant 'Congrats on that enormous belly of yours!' But it just seemed so random. And it was made a wee bit more uncomfortable because there was another young man walking extremely close behind me (because, well, I walk slowly, no, excuse me, I waddle slowly these days. And people seem to think that by walking really closely behind me when there is not enough room to pass will make me go faster. I just want to turn and hit them and remind them that I would walk faster if I COULD.) Anyway- I am pretty sure that creepy/nice man thought that close-walker dude was my baby-daddy.

So. Out of the ordinary nice? Was he just telling me congrats in a situation when our culture usually has us walking by each other with our heads down? Or out of the ordinary creepy? Was he just being an ass while in front of a few people who could have been his buddies that know him as the guy that will say anything to anybody?