Guy colleague fine in a group but doesn’t want to talk alone

I (f29) used to get along well with my guy (32m) colleague , we bonded over our similar anti establishment mindeset and unionship. One time he gave me a lift to my bf’s and things seemed to be fine for a while.
Recently, I acted a bit off with him as I was going through alot but didn’t explain this, I thought things would revert back to normal after I see him next at work.

He has been noticeably more distant with me, for example if I wave enthusiatically to him, he would just be quite low energy, but will spud the next person he sees (usually a guy tho).
He used to stick around and chat but nowadays he makes it a point to leave when other people are leaving to go back to work and won’t stick around to chat, he’s done this about 3 times so its enough to notice.
I’ve not asked him if everything is okay and instead I’m kind of throwing similar energy to him. I know he’s going through a break up atm, but also heard that relationship was casual..
so im just trying to understand why he doesn’t want to talk to me anymore if its just one on one..have I put him off?

tldr: guy colleague and I got along well, now he makes it a point to not talk alone if its just the two of us..