boyfriend issues

I was supposed to go to a bruins game with my boyfriend tomorrow than this whole thing happened and I say that I'll see him tomorrow then he looks at me like "oh shit" and I realized he probably made other plans. He did. Thinking he thought id sold them so he made other plans and would let me take the tickets. Then he's like oh no I'm going to the game... With my brother. I'm mad. Do you think I'm over reacting or that being this angry is understandable?