Is there anything wrong with my hamster?

[chubchub]

I may have allergies or a cold, and I keep one of my hamsters in my room.

Last week, Sammy has been sleeping a lot and I asked for advice in another forum. They told me to change his diet so I did.

My long-haired Syrian usually wakes up at around 8-9 PM then I would let him run around my room and he would be up until 7-8 AM.

A few weeks ago, he's been going to sleep early. He's not sneezing, lethargic
or have watery eyes at all. He eats a lot, goes on his wheel and seems healthy but he's been going to sleep early.

Last night, he was up at 8 PM and he went to sleep around before 1 AM

When I woke up, he was sleeping still. I tried to change his diet already.
I stopped giving him yogurt drops and I picked out almost all of the sunflower
seeds in his hamster mix. I clean his cage every week. I used Aspen bedding
but I ran out.

I bought Critter Care Natural bedding (grey) from Wal-Mart. It almost look like Carefresh so I thought it would be safe. Now, I just read from the internet that the grey stuff can trigger both human and animal allergies and tends to have a higher dust content.

I'm on my way to work and I can't change his bedding til later. And also, he's been sleeping a lot even before I used Critter Care Natural bedding.

Is there anything wrong with him? Does he have a cold? What should I do?