Am I Overreacting?

Long story short..
My husband was supposed to go to a dinner with his siblings. It was supposed to be just the siblings and that was fine, didn't feel any type of way about it. But he comes home and then tells me about the fun he had with his brother and his brothers friends and both of his sisters husbands were invited. He asked me if anything was wrong and I brushed it off, not sure if I should even mention my feelings towards it. I just feel left out. Don't know if it's because I'm pregnant and they went out to a bar setting or what. How would you guys feel? Would you even address it or just let it go? This is the first time I've felt this way in his family.