it is sad day.
are you on your way to the vet now, or already been there, or what?
same boat, kind of: dog I had for about 2/3 years had a problem with seizures/convulsions, ended up bleeding a lot, apparently. we had to have her put to sleep/mercy killed, so that she was out of pain. (it happened multiple nights per week, for ~ a month, IIRC)
also, the cat that was older than I was (at the time) ended up getting too old. couldn't eat, couldn't jump like she used to, and ended up just laying on the couch. I'm not sure if you could see it, but you could definitely feel her ribs. she was skinny to begin with, but that's another level. had to have the same thing done with her, due to she couldn't chew/eat/move, though I chose to stand/go in the room to be with her. wouldn't have been able to live with myself, leaving her alone like that. <3
edit: cat was 19, I forgot to mention. yeah. old kitty.
good luck, bro. death happens to us all, eventually. it's what you do with the life you're given that makes the difference.
or some philosophical stuff like that.
tl;dr, it is sad day.
never mind, moved to other thread