Mary_j: there could be a lot going on with your cat that is causing these things. The best thing to do would be take the cat in to a trained veterinarian if you are worried for it's overall health.
Questions or assumptions on my end might be that the cat had some sort of trauma. (being hit hard, falling wrong, etc) But it could be other things such as sickness, disease, etc. Possibly it's just as simple as an upset stomach for a few days. (Can you tell if stools are any different?) Can't be sure what it might be with these generic ailments.
For older cats it's very typical for them to be "listless and unresponsive", seeming tired all the time. However, for a cat under 1 year of age this is not as typical and could be indicative of other issues. Especially when the cat is acting totally different than it did just a few weeks ago.


