Newly adopted cat and so I can't tell if behavior is normal

Hi, I'm hoping to get some insight and advice.

Background: We adopted a 1.5yo cat on Sunday (today is Thurs) from a local shelter. We are not sure where he originally came from, but he was listed at the shelter as a "stray" that had only been there a few days. We visited him twice before being able to take him home. Both times he was extremely cuddly and perky and playful and we were told by the shelter employees that he had been that way with everyone there as well. He was neutered on Saturday (the day before we took him home), and his records indicate he is up to date on all his vaccinations and meds. The records also say he tested negative for FIV.

The first day we brought him home he was EXTREMELY playful. He wasted no time coming out from under the bed and exploring his "safe room", i.e. our bedroom, and so we opened the door and allowed him the option of exploring the rest of the 2 BR apartment, which he did. He hung out in the living room playing/sleeping all day and slept in our bed that night.

Problem?: The second day home and up to now, his behavior has changed what I think is dramatically, but my boyfriend thinks I'm overreacting and so I'm trying to figure out what to do. The thing that worries me most is that he is not nearly as playful as he was. He has been sleeping almost all day for 4 days. He will wake up to eat, and he will sit and stare at us for a little while, but that's it. No engagement with toys, no coming over to be petted, etc. He allows us to pet him but does not show nearly as much enthusiasm about it as he did at the shelter/at home the first day. We think that he may be stressed out and tired from such a huge change and showing delayed signs of that now, and so we are trying to let him be and sleep as much as possible. 

I noticed that he was sneezing on Monday and Tuesday. Not constantly, but every now and then. I did not want to take him to the vet for fear that that might actually exacerbate any illness if he was already a little weak from the move. He has stopped sneezing for the most part (he still sniffles every now and then) but this morning after he ate breakfast he had a very odd "fit" of rapid-fire sniffles for about 10 seconds. 

He has been eating regularly (but with slightly decreased enthusiasm as he had the first two days?) He will run into the kitchen when he hears his food being prepared, but he does not finish his bowl in one go as he did the first two days. I have been weening him off Science Diet hard food and on to a mix of grain-free wet and dry food (still mixing in portions of SD and I tested several canned options til I found the one he seemed to like best).

He uses the litter box but I noticed him sniffling for the first time the first day when he came out of it and so I changed from one clumping, clay litter to another clumping, clay with less dust. I also have another litter box set up with pine pellets which he will not use.

Any suggestions? Am I completely overreacting? Is he just adjusting or should I take him to the vet?

Thank you! (I'd like to add that I'm trying not to show worry when I'm around him )

He sounds fine, maybe a slight URI flare-up from the stress of the shelter and coming into your home. It's like a kitty cold. Some infrequent sneezing isn't something to worry about. Cats in shelters generally sleep poorly and will either struggle to eat or scarf their food from stress. 

Overall it sounds like he's adapting to your home. He's getting in lots of sleep, not scarfing his food, and socializing with you. Give him some more time and enjoy his cat-ness. 

Congratulations on the new addition to your family and welcome to TCS! 

How is he doing today? It's great that you're so attentive to his behavior. To me it sound like he's not well physically. I can't think of anything else in this situation which would make a cat active on the first day, then sedentary on the following days. If he's still "down" I would definitely call the vet for a phone consultation. The shelter should be able to let you talk to the vet and see if the cat needs to be brought in for further assessment. Good luck and let us know how he's doing!

Thank you everyone so much for your responses and PMs.

I did decide to take him to the vet yesterday. They took his temp and he had a fever of 104.4 and was diagnosed with a URI. The doctor expressed concern that his fever was high for a URI though. They gave him subcutaneous fluids to reduce the fever and he is on a 7-day antibiotic regimen (Veraflox). His stool sample tested negative for parasites.

He seemed to respond quickly to the treatment yesterday. Last night he was in much higher spirits - still sneezing, but eating very heartily and super cuddly. This morning... I can't tell. He is sneezing way more than he has so far and there is a lot of mucous. He followed us around and ate about half his breakfast and now he is sleeping. It's hard to tell if that is normal for him because all I have to go on are the few times we met him when he wasn't sick. He did not poop at all yesterday and he hasn't today so far (the first few days he'd go once a day, usually after eating).

I guess I'm still pretty worried. Called the doctor this morning and she said it is normal for them to get worse before they get better. Fingers crossed that what's really dragging him down is bacterial in nature and will respond to the medicine.

for him! It's not unusual for both negative and positive changes, i.e., ending up at a shelter and then moving into a new home, to lead to an illness. It's a good thing you took him to the vet's office. Veraflox usually works pretty quickly and at the very least will prevent secondary bacterial infections. :cross: