The reason his feelings “changed” overnight is in his mind, he wasn’t sure about you to begin with but didn’t let it show. He can’t go from really liking you to not liking you unless you did something extreme.
Yes, his feeling can change overnight but not as you think. While all men are different, what I am about to talk about is a large majority of men. I am going to tell you EXACTLY what goes on in a guy’s head, what actually happened, and if his feelings can change that fast.
I have been a guy who liked a girl one day and then overnight, my feelings have changed.