What does it mean if a guy says "night night you" or "hey you" ? Does it mean he's not that into me because he doesn't use my name or a pet name?

1. He may have had so many girlfriends that he cannot keep them straight without mixing up their names.
2. He could have a poor memory and doesn't want anyone to know.
3. He doesn't remember your name.
4. It's a quirk of his.

Try calling him by some made up name and see what he says, or you could try asking him directly.