I think he likes me but idk...?

so i was driends w thi s guy last year we occasionally talked ovr the summer and we jst started taken again. he is being all flirty and is ancious to hang out. he asked me if i have a bf i said no, i asked if he has a gf he said well not tecnically they bothplan on goin out once they hang out more..im confused now. he is being super flirty yet not so much at the same time. yesterday he invited me to this thing which is tonight. aftr i said i can go he goes.. kelsy is gunna be there =] thats the girl. he didnt tell me b4 so now its really gunna be occward. well fortunatly im sick w the flu today so i dont think i can go but im hangen out w hem friday. i really really wantt to but now idk if he is still flirting w me cause of kelsy but he still acts lke it..im sooo confused! plz hlp