call everytime.

He's raising because he hit a bit of flop and you have no chips so he figures he'll just put you all in. You probably have the best hand here.

Never play poker with less then 4/5 off afull buy-in.

Imagine you have a full stack. You raise to 5 times the big blind preflop. On the flop you bet 2/3 the size of the pot. After that you re-evaluate depending on what happens then.

Keep reading and posting. You've got a lot of learning to do!