Is it cause of valentines day?

theres this one guy that i met this year and we became really good friends. Sadies is coming up and its on Valentines Day. I asked him to be my date and he said that he had other plans for that day. I was like koo. whatevers since we were just friends but after that he started acting super wierd after that day. It just wasnt the same. Why is he actin the way he is...hes been ignoring me and when we do talk, hes like stiff and has yes or no answers....