I don’t know what’s wrong with my 8 month old cat

Hi everyone! I’ve had my 8month old cat Blu since July. In early January, my husband and I adopted another kitten named Bubbles. When we finally got out of the introduction stage for our cats, Blu and Bubbles would play all the time and groom and sleep together. Although when we adopted Bubbles from the shelter she came to our home with an upper respiratory infection. Blu never showed any of those symptoms when she after playing with Bubbles. Bubbles received medication for her infection and is much better with a little sneeze here and there. The issue with Blu: During the entire time of bubbles being sick, blu never showed any symptoms of any illness. We’ve noticed a change in blu, blu barley eats, she nibbles on her food. She sleeps more than usual and doesn’t play with bubbles anymore, whenever bubbles tries to play with her, blu will hiss and slap at her. Also, blu’s face is a little puffy. Blu barely uses the litter and I almost never see her drink any water. I try to play with her, but when I do, it seems as if she wants to play but something is holding her back. I really hope she’s not depressed or worse. Thank you in advance to anyone with feedback!  

Hello!  We don't know much about depression in cats, but there are many more illnesses that would need to be ruled out before coming to that conclusion.  It sounds as though Blu has a reduced appetite, sleeps a lot and her face seems puffy.  I'm not sure over what timescale this has occured, but it may be possible that Blu has sustained a bite or scratch to the face.  Cats have some nasty bacteria under their claws / in their mouths, which cause symptoms of an infection nearly every time, including a high fever (you can only really tell with a thermometer in cats but it may explain the lethargy) and a lack of interest in food.  Cat bite holes are tiny and are almost never seen and rarely suspected by the owner.  It could be that if Bubbles was feeling ill, she was drawn to an uncharacteristic snap at some point.  However, these infections can progress and become quite unpleasant;  further, other illnesses that may present in this way include liver disease, pancreatitis and more more serious ones including severe dehydration.  For this reason, we would advise that you call your vet or their emergency representative for triage (eg for the case to be assessed in order that the vet can judge how urgently it needs to be seen).  Best of luck with your little one!