Friend with feelings?

I'm married, have 3 kids, and work part time. I will be transferring my job to a place closer to home. I've made some good friends at work. One was a guy that has told me when I transfer he wants to come in and "bug me" at work...basically just to stay in touch. I thought innocently of this. Such as it's nice to have people that switch stores to stay in contact with friends, others in the store have had customers do that. Then he asked to be my Facebook friend and I was like ok I have others from work that I'm friends with. Then he randomly Facebook messaged me, it was all platonic but still made me feel awkward. Now tonight I'm in the ER with my daughter when I get a Facebook messenger notification at 2 A.M. no less. It's this guy and he said "It was good to see you yesterday!". That really threw me for a loop and I was thinking that doesn't sound just as friends to me. Am I over reacting? I will add he knows I'm married and have kids because my profile pic is me and my whole family and I'm not interested in him at all.