My Pussa (14 yo) had very very bad breath, and had pus in back of his throat, weepy eyes (green), nasal discharge, was off his food and not drinking much but still walking and alert etc. I gave him his food and drink by hand, cuddled him and watched him overnight and he seemed better in morning. Had his antibiotics, another feed and drink and then about an hour later suddenly let out a cry, was on his side and was limp. He got a little better but his leg jerked a little. Went very sleepy and more cuddles while waiting to go to vet. Sadly, by the time we got there he was just out of it....then we had him euthanised. What was probably wrong in the first place and why did he go like this???? Any ideas?