[RubyDG]

I'm a little concerned over my Syrian boy Spike. He is 5 months old and was pretty much tame from day 1. He has always been a barely restrained bundle of energy and constantly demanding attention. I usually give him about 2 hours free range play time a day and even then he still throws a little strop when I put him back in his cage. For about the last two weeks (roughly) his behavior has changed. At first I thought maybe it was the weather because it's gotten colder (although the room he is in is usually heated). I've also just had surgery so for the last week and a bit he's been somewhat ignored. He's had his food and water changed obviously and my husband's taken him out for brief periods but he's not had the kind of attention he's used to. He is eating and drinking normally and using his wheel. I've given him more than one health check and all the boxes are ticked, I even checked his weight and it's the same'ish (2 grams less but the scale is finicky and tends to give different readings - I've ordered a new one). The thing is he just seems to have less energy - not lethargic by any means just not interested in running around like a maniac. He has also been reluctant to come out his cage and is essentially ignoring us. Usually I barely have time to get the cage door open before he's jumping into my hand but now I'm having to coax him out with food. I just took him out for play time now because he was running on his wheel and he wandered around the room for a few minutes and then just came and sat by my feet (he will usually sit on my foot with his paws on my leg when he wants to either be picked up or go in his cage for a water/food/potty break). He just doesn't seem to be himself. My husband thinks it's just the weather and because he was ignored for a little while or even that he's just moving out of the 'baby' stage. I'm worried enough that I'm contemplating taking him to the vet but as there is nothing obviously wrong I think he'll probably just tell me to keep an eye on him. I don't know if I'm being paranoid because I've never had a hamster before but I can't shake this feeling that something isn't right. I guess I'm just looking for reassurance and wondering if anyone has had this happen or has any ideas if something is wrong or not?