Most Helpful Guy
Yes he's over you that quickly. It's a skill we guys have. You can find literally dozens of questions about this ability on this website.
"did he just not care "
He very likely did care. But part of this ability to get over a girl so blindingly fast, is that it has the advantage of making the girl doubt the *entire* relationship, frequently hurting her in the process. For some guys post break-up, this aspect is appealing.
Most Helpful Girl
It sounds to me like he's hurt and just going through a phase where he wants to make you feel that way.