why is he being like this?

There could be multiple reasons. Hopefully he would be honest with you and tell you if there is a problem. Communication is vital in a relationship and often gets brushed off like it isn't a big deal. You can try asking him, but if persist in ignoring you then you have to take action. If he isn't enough of a man to at least talk to you about whatever his issue is then he isn't worth your time. Best of luck to you.

Yeh reasons can vary and communication is key, if he is ignoring you for awhile it means he lost interests and you can move on and be single again.

That doesn't sound good. You might have to move on then. The love game can be very painful, but I can guarantee when you find the right man it will be worth it. Brush off that loser and continue your life.

If he's busy with work or school (depending on age) but if he needs time to think, then there's not much you can do about that.