Lots of dieting people can be grumpy. They want to lose weight, and many try so hard, then they eat something they shouldn't, and get angry with themselves, tending to take it out on others. As far as that goes, some of them in WW may be some of us too, they may be hurting and not knowing why. Or, they are just grumps to begin with, that happens too!
You can do this. I know it's not easy, I've been trying to lose weight most of my adult life, even before that. This last year I finally did it, now, I will spend my time keeping the weight off!!!
Good luck!