My Jack Russell Terrier is sick... at the beginning of the day, he was squinting a little bit and had slightly red eyes. As the day has progressed... over the course of about 12 hours, his situation has declined a lot. He keeps his eyes almost exclusively closed as he walks around and stuff, is acting lethargic, and is whimpering a bit. When he gives me those doggy kisses, they're pretty warm... leaving me to believe he has a fever.
I believe he's about 2 years old. I'm not certain but I think the vet is closed right now (it's 9:47 here). What should I do? Could this be a very serious condition? Is it possible he could die by tomorrow morning?
EDIT: Other notes... he has pooped 3 times today, each time a decent amount. I don't know if I'd call it diarrhea... just normal poop to my eyes. He appears to have drunken plenty of water but has not yet touched his dinner, which he was fed at about 6:00. He is shaking right now. Also I suppose it is worth noting that I haven't seen him scratching at his eyes.