I THINK MY GYM TEACHER IS FLIRTING WITH ME?

ok, so im in the 7th grade and i go to a Christan school. my gym teacher is about 40ish years old. he is always very friendly with me. i was always kinda a teachers pet to him because i am on the basketball team and im very good and i keep my grades up. But he seems kinda stalkerish lately. He is also very frendly with me and all the other girls in my cl. he put his hand on my back and i kinda feel weird about this. he did this to alot of other girls too. is he just being frendly or is he crossing the line? HELP ME :-)