high alert kitty watch

I'm beginning to fear Blackie might actually be sick. For the past few days, he's been vomiting up clear bile, some hairballs. No food. I haven't seen him eat or drink much, or use the litter box. He doesn't feel feverish, but he's quieter than usual, preferring to watch Charlotte play by herself, crouching in a corner with saucer eyes. He still chases the laser if he hears the button clicking, but he's not his usual boisterous, mischievous self. We just bought a new bag of their regular food, but Charlotte isn't acting any different.

We call Blackie "garbage cat" because he'll eat just about anything. He chewed up the rubber strap on my computer power cord. I've caught him with bits of plastic, foil, wood chips, tiny rocks. He's usually ravenous -- curious about whatever's being opened in the kitchen. But not lately. Because of how he usually behaves, I'm afraid he might have a bowel obstruction. But his belly isn't distended and he's not opposed to being picked up, so I don't know. I'm worried.