One day isn't a worry as long as temps are correct.
However, with an open table, temps and humidity is almost impossible to maintain. Get the table covered, making it a closed chamber. Humidity needs to be 80% all over. Basking spot 95-100 and over all temp day and night no lower than 80.
Get the needed changes asap.
I'm thinking it isn't warm enough (like Barb says).
Get the baby up in the a.m. and set it in a bowl or warm water (the water should come up to the middle of his sides). Then leave him there while you prepare his food. Put the food out for him then place him in front of it.
In the meantime, try to figure out a way to cover that enclosure so you can keep the cooler air from your house out of it. With a cover the light will be able to warm up the whole enclosure. Also, wet the substrate, and the cover will help the warm air to be humid.
I have another little helpful hint for you: That bowl is hard for a tiny baby to access. Because of their shell, tortoises don't bend. If your tortoise wants a drink it either has to stretch his neck way far out, up, then over and down, or he has to risk tipping over on his back as he climbs up the straight sides. The first option isn't one he's going to do because it puts him in a very vulnerable position to predators. I suggest you get a clay plant saucer and sink it down into the substrate so he doesn't have to actually 'cliimb' in, he can either reach his head in or step in.
Also I see one light fixture. I'm sure its light/heat/ uvb
That us not enough to keep him warm at night as it needs to be off at night. If it's a Coil bulb stop using it. If it's a mercury vapor bulb stop using it. Put a ceramic heat emitter in it and get a tube florescent uvb light.
Build a frame over the enclosure high enough you can hang the lights inside the cover you will place over the frame.
Read the closed chamber threads and the leopard caresheet.