What is this supposed to mean?

ok i met this guy through my friend who had liked him. We started talking and now he flirts with me a lot and comments my pics on fb. He asks about me to my friend so i asked him if he did and he completely blew up at me and now after that hes like 1 min. hes nice and flirty like that and the next hes a real jerk. he'll text me and say he loves me and ill say no you dont you wouldn't be a jerk to me if you did and he said ight....ok then? What is all of this suposed to mean is he just flirting to be a guy. but then why does he get a mad? I just don;t know why sometimes hes really nice and then not the next? If you could give me any kind of idea it would be greatly apreciated(: