His Highness just isn't himself at the moment. Something seems off but I'm just not sure what.
He's moving quite slowly, lethargically, almost a tiny bit unsteadily. I thought he had hurt one of his back legs at first. He usually bounds down the stairs in the morning but is taking them one at a time now. He hasn't gone outside today, has used his litter tray instead (normal bowel movements), because he seems to find the cat flap a bit awkward. He's sleeping lots (that's not particularly unusual) and instead of his full volume bellowing miaow he gives a pathetic little mewl every now and again. He's been like this since about Saturday but this is the first day he hasn't gone out.
I've poked and prodded all over. He doesn't seem to be in any pain, he hasn't responded unusually (e.g. with a miaow, swipe or bite) when I've touched any part of his body. I can't feel any lumps or bumps or unusual hardness or softness, there's no swelling or wounds anywhere. His eyes, nose, mouth and ears are all bright and clear. He's eating normally.
He's 3. Do you think he's just a bit under the weather? Should I take him to the vet? I'm not sure what I'd say - "He's too slow" doesn't seem like a good enough reason!