I am in love with my best friend...?

about a year and a half ago, i was at my friends birthday party (lets name her Aly) and me and my friend (lets name him kyle) were hanging out. ever since then, we have been BEST friends. we are inseparable. everybody jokes around saying that we are going to get married and we kind of laugh and say ewww or whatever. he flirts with me and pretty much every other girl at my school. like he gives me and aly like kisses on our cheeks, and just flirts with us. so this past school year, this new girl (lets name her sally) switched to her school, at first, everyone thought she was wierd, but then she sat with us at lunch and her and kyle found out how much they have in common. i have liked him since aly's party, and ever since then i have been trying to get him to like me too. i was almost there, but then sally came along and ruined it all. i sort of hate her because she spends so much time with him. whenever i am talking to him, she just interrupts me and talks to him. i get jealous whenever he flirts with other girls, and apparently, ally says i give them dirty looks. lately i have been very clingy to him, and i follow him everywhere. it seems like hes getting kind of annoyed with me. the worst part, is that next year, i am going to a different school and sally is staying. so then she will DEFINITELY replace me. but i dont know what to do... i dont really want to tell him that i like him, because 1) he probably doesnt like me back 2) it would ruin our friendship.... but i want him to like me more than anything. i have been trying to get him to like me for the past year and a half. should i move on? i dont know if i can....