Do you ever wake up with your panties in a twist for no discernible reason?
Just in a huge grump, irritated and lacking in patience. And you don't know why.
You know you're not PMSing, and you don't have anything specific that you're fretting about.
You slept enough. You've been eating well. You've been exercising. You aren't stressed. Nobody has done anything unkind to you. The post-election mood in town is great. Everything else that you can think of is pretty manageable.
And yet, you know you'd kick small children and take their candy if they got in your way?
Yeah, me neither.