Why is he suddenly acting like this after such a tiny exchange?

Anonymous
I first met this guy back in early November of last year at my new job. I followed him on Instagram before that, he had accepted, and then followed me back. On my very first day of training for the job— I kid you not, he coincidentally saw me walk by him like twice and texted me saying that he would come upstairs to see me after he viewed and replied to my story indicating that I was there. I had absolutely no idea that he was already working at the same place I had just signed up for. He eventually got upstairs to where I was, sat down across from me, and we talked for I believe a good 30 minutes. We’ve only been familiar with each other for 7 months now. We’ve never had any other actual conversation aside from the one we had on that day. We only ever say hi whenever we see each other in the halls at school. Lately, not so much. This is where I’m curious. The last time we ever texted was when he replied to my last story where I indicated how nice a certain restaurant in the community we work in is, saying that I should wait until I see the one he’s at, in a humorous manner of course. I replied about 30 minutes later merely asking if they got outdoor dining. Ever since that text message, he’s been very distant and either immediately turns away or looks down at his phone whenever I see him or he sees me. Crazy how one can flip in an instant. I just don’t get it.
Updates
10 mo
+ After I sent him that message, he left me on delivered during the week and then on seen over the weekend.
Why is he suddenly acting like this after such a tiny exchange?
7 Opinion