Is it normal to feel like this?

My best friend is at a banquet tonight, so we haven't talked (I just sent him a text saying goodnight however). He asked a girl to go with him, but just as friends. I feel really jealous, is that normal? He's 3 years older than me; so the girl he asked out is his age. But I'm just in a mood where I don't feel like doing anything or talking to anyone..?