Ask why.<br />
Respond accordingly.<br />
Ask them what their problem is. If they were a real friend they wouldn't do that.
Doesn't sound like much of a friend.... Unless you are the one at fault, and don't want to admit it.
Find a new friend.
That's not a true friend move on. She doesn't deserve your friendship
Give them some time to blow off some steam. If they want to talk about it later and apologize after then it's all good.
annoy him till he notices you