I am feeling irritable today and I can't tell if I have legit reasons to or if it's just my hormones…

I am feeling irritable today and I can't tell if I have legit reasons to or if it's just my hormones which is irritating. Now I'm at a bridal shower where everyone is drinking and talking about how skinny they are getting. I am trying my hardest to be fun but I can't help but feel pissy. I don't want to be that girl.