I'm extremely conscientious about printing or making movements that might reveal my gun.
Yeah I kind of figured. I've always gotten the impression you are a conscientious carrier.
Still uncomfortable with the fact he pulled in beside us and stayed in his car until we went in the store.
You said head down in your OP. It's possible he was texting and you didn't see the phone. What was the topic though? That's the question I suppose.
The one place he MIGHT have made the gun was in the restaurant where we ate. Possibly while I was sitting, the chair may have pressed against my shirt and the gun printed. He then may have kept his distance and followed us to the drug store. Really, other than being on drugs I can't think of anything else.
Now you're kind of getting into a lot of "mays", and "mights". In short, it sounds fishy to me too man, and I think paying attention and going on alert was the correct reaction. Your Spidey sense tingled, and you were on the look out.
It isn't paranoia, it's just vigilance. I think calling the cops would have been a little unwarranted. Now if he had deliberately followed you to the other store, then I maybe would have called, or simply driven to the police department right then and there.
It may have been something, or total weird coincidence, and nothing at all. He may have gone home and said "Honey, you should have seen the dude staring at me at the store. He made me so nervous I left without buying what I was there for....... and now we have no toilet paper."
You know I've gone into stores before, not found what I've been looking for that should have been there, and left the store without buying a substitute simply out of anger. If I'm in that kind of a bad mood, then everything makes me mad, including the guy who keeps staring at me. You said he was on his phone? Maybe he was fighting with his significant other, and you watching him made him mad, so he responded in kind.
Like I said. Keep an eye out. I think your gut is the best judge of the situation, as none of us were there to observe. I hope you never find out what the cause of the weird behavior was, because that means bad things are going down.