I am a little concerned about my cat's health

Lately, my 7-year old male cat hasn't been quite acting like himself and I'm a little concerned about his health. Here are some things I noticed over the past several weeks:

1. He normally likes cat treats, soft and crunchy. Lately he's been only eating soft treats. If I give him crunchy treats, he will start to eat them, but then spit them out. Sometimes he'll spit them out half-chewed and other times he'll just suck on them and spit them out whole.

2. He shows some minor signs of trouble when eating wet canned food.

3. Normally, he is always excited to eat a bowl of wet food. I feed him at the same times every day. I always call him to the kitchen when it's time to eat and he always comes running. Tonight he did not come to eat his dinner at all. He was not the least bit interested.

4. He's been making this noise with his mouth - similar to the noise a human would make when they are thirsty. The best way I can describe it is when you open your mouth and sort of smack your tongue a few times.

5. For a little while tonight, he was making a sort of sneezing noise. Not a full-blown sneeze, but the kind of noise you would make if you got dust up your nose.

I'm mostly concerned about the fact that he was not at all interested in eating his dinner tonight. Normally he comes to me when it's time for his next meal and tonight he didn't come at all when I called him to eat.

I took him for his annual checkup a few weeks ago and the vet didn't notice anything wrong with him.

Does anyone have an idea of what could possibly be wrong? Should I be concerned?

I may be overly concerned because his brother died of kidney disease a few months ago and I really don't want to lose another cat.

Any advice would be greatly appreciated.

Has he been drinking normally? How is his litter use? Does he seem generally uncomfortable, lethargic, restless?

He's been drinking water as regularly as he always does.

As far as I can tell, his litter use is normal too.

I don't think he's been any more sluggish or tired than normal either.

#4 on your list is one way cats display stomach troubles. That plus his lack of interest in food adds up to a vet visit for me

The noise would make me think hes smacking lips cause hes sick to his stomache.
I would think he may have picked up a bug from the vets. Since he was just there call and see if they can help over phone or need to see him. VERY important a cat eats or it will get very sick in matter of a day or two. How was he for a teeth check? Make sure they look at that VERY well. Any strange smells from mouth?

Usually your symptom 4 the smacking noise is caused by tour can being Nauseated .That would explain why hes not eating. My other thought is a bad tooth. He really should be seen by your vet soon

I'm thinking bad tooth or upset stomach. Vet visit is def. in order.

Is this the same cat who you posted about few months ago? Has he ever had a dental? I would ask how much it is and see about doing one if possible-maybe there is something going on in mouth that will show on xray

Yes, it is the same cat. He started eating normally again after I made that older thread and then he had his annual checkup in August which went well so I wasn't too concerned until the other day.

I decided to take him to the vet this past Thursday. The vet checked his mouth and said she saw no signs of redness or sores. However, he did have a slight temperature (103.5). The vet gave him an antibiotic and on Friday his temperature went down to 102.7 which is a good sign.

He's eating his wet food normally again, but he doesn't seem to be interested in the dry food (Friskies) that I normally give him throughout the day.

Does anyone know if there are any softer foods like Friskies (not wet canned food) that I can try out and see if he's interested in until I can get an x-ray done?