african sulcata not mainting heat

by Robaloie & Drew
(Tucson, Az)

We have 3 African sulcata tortoises, a little over a year old. One of which was flipped upside down this morning. He has been inside his shell ever since and has been very cold and not able to maintain a warm temp like the other two have. He barely moves, and his rear end next to his legs is swelling out of the shell.

I obviously believe he is sick of some sort. Any advice or knowledge on this topic would be greatly appreciated. Currently can't take to a vet until monday. Please any advice or help would be greatly appreciated.