Am I overreacting?

So I've had an incredibly shit week. I've been feeling so down and upset. 
I haven't been able too see my partner as he has been so busy with work. 
We were supposed to see each other tonight, which I was really excited about because all I've wanted is a hug as I have felt so upset. 
But then he tells me he's going too have beer with the boys. 
He hasn't seen them in a while but I just can not stand making plans with someone and getting snubbed for something or someone else. 
I would have probably been okay with it any other time. But right now is when I needed him most. 
So, am I right too be upset and a bit angry? Or should I just let it go?