Yes, I did. It just took time for me to type a response to you; sorry for the delay.
Thanks for the answers to my questions and the additional information.
Gum color is normal which is good. The fact that he didn't react too strongly when you felt in between his legs is also a good thing. When male cats become lethargic, I always worry that they may be blocked and can't urinate. When the bladder distends, they typically act quite uncomfortable or painful when you feel in this area. Since he usually urinates outdoors, we can't entirely rule out this as a possibility but it seems less likely given his lack of a significant reaction.
1. I absolutely understand about not being able to take his temperature but if you manage to do so, it might be helpful. Normal is between 100 and 102.5. If it's elevated, then, of course, we'd have to wonder why. The various possibilities include a viral or bacterial infection or the early phases of an upper respiratory infection or even a condition called Fever of Unknown Origin. This latter condition is pretty much what it sounds like....the patient is running a fever and yet we can't determine an underlying cause. In most cases, once the fever is reduced with medication, the patient returns to normal within a very short period of time.
2. Another possible explanation for his behavior would be pancreatitis. Often these patients don't have much interest in food and will often act lethargic. This is another condition for which we don't have an explanation as to why it develops but it almost always comes on acutely with no warning. We have several different tests for pancreatitis but I've come to doubt their reliability in some cases.
Treatment primarily consists of fluids and pain medication since we believe pain is why the patient behaves as they do.
3. I suppose there could be other possibilities such as problems with his heart or other systemic disease but he's awfully young for such problems.
4. Some cats will just have "off" days and we're none the wiser as to why. I suspect a virus but have yet to prove it.
Unfortuantely, I wouldn't advise any over the counter medications since cats are so sensitive to many of them; I wouldn't want to worsen the situation unless or until we have a better idea of what might be going on with him.
If at all possible, I'd try to gently feel all over his body for any sensitive or painful areas. If he had an encounter with another critter when he was outside (even a day or so ago), he may have an abscess or wound which is now causing him problems. If that's the case, you might be able to detect where it's located.
If you manage to take his temperature and it's high and/or he continues to worsen in any way (has trouble breathing, for example) and/or you locate a specific area of sensitivity, then a vet visit may be prudent.
Otherwise, if he's continuing to eat, I might monitor him for the rest of today and reassess tomorrow.
I hope this helps. Deb