Both cats & dogs can get URI (Upper Respiratory Infection).  It’s more common in cats than dogs & is easily spread from cat to another.  Common symptoms that they could be sick are sneezing, ocular or nasal discharge, congestion, fever, lack of appetite and energy, increased salivation, and inflammation and/or ulceration affecting the mouth, nose, or eyes.  If any of these symptom’s are happening call your vet.  Making your pet feel better is simply if you take care of them right away.