Please help, I can't stand to see him like this

[SketchpadsRUs]

My oldest can, who is only 8, is very sick. Last night he started 'open-mouth breathing', sticking his tongue out, drooling ALOT, and began coughing (gagging) occasionally. There was also a slight wheeze to his breathing. Also, he just LOOKED sick, in his face and eyes.

This morning we took him to the Veterinarian. He checked his mouth, saw what might be a sore/abscess in his mouth, but didn't seem to concerned with it. He checked down his throat the best he could, felt around his chest alittle, and took his temperature.

He said my cat had a slight fever. He said most likely the cat ate something bad for him. I explained that he was an indoor cat, and that we don't use poisons around the house. My mother does have a Philodendron in the kitchen (hanging), but the cats generally leave it alone. He gave him two shots, and antibiotic and vitamin K. He gave me pills of each as well.

Now its very early the next morning (Sunday, Veterinarian visit was Sat morning) and my cat is still doing terrible. He's gagging more, almost constantly. Still drooling with an open mouth. He has not eaten or drank anything, I do not think he has gone to the bathroom. He took one pill each Saturday night. It still kills me to look at him, he looks so miserable.

He does seem to move around a bit more, even went to his favorite spot by the window, but he shows no interest in us, the other cats, or food/water/treats/bathroom.

Also, we had recently what seemed like a cold/flu hit our cats the last couple weeks. A cat would sneeze alot for a few days, then stop. By then another cat was sneezing. Each lasted a few days and we weren't too concerned. However, it did not seem to affect my oldest, but then out of nowhere all these symptoms started.

I could ask questions forever, but the main things I want to know are:

What is wrong with my cat?
Does the Veterinarian seem to be doing the right thing?
Is there anything I can do to help my cat?
When do I start worrying about him not eating or drinking?
Any chance something foreign is inside him and then Veterinarian just missed it?

Please, I'm going nuts. If you have any thoughts at all, please reply. Thank you so very much for your time.

--- Steve, concerned immensely about Kitty