Why didnt my ex want to be friends..?

we had like an amazing realtiship for 4 months (were in 9th gr) and all the sudden he changed and we fought alot too.and on sunday he broke up with me saying he lost interest in me and hes like "okk soo byebyee" and that was the last time i ever heard from him..i see him in the hallway and he put his hood up so i dont see him or he will like be behind me and look at me..But why didnt he want to be friends??:/ and will he ever text or talk to me ever again??