Sabby's been vomiting since Friday night. I've been paying attention to his litter box and as far as I can tell he hasn't had a real bowell movement since at least Thursday. He vomits twice then tries to poo, but can't. He tries so hard that he grunts and picks his back legs up and they scoot across the box. I've tried putting canned pumpkin (not pumpkin pie filling) in his food, but that hasn't had any results (except he eats less food; he really hates pumpkin). He's got a vet appointment this morning. In the meantime, would anyone like to venture a guess as to what's going on?