i lost my guinea pig today

we've got no idea why, cuz he was doing so well. he'd been off the meds for the bladder stone for awhile and while he hadn't had his follow up yet, he was doing so amazing and better. on thursday our AC went out so we took him over to my dad's while we stayed at my uncle's. both my dad and brother (who had him in his room there all weekend) said he was acting just as squeaky and happy and hungry as he always is. they brought him home yesterday evening and I...i don't know what happened.

he didnt finish the lettuce my dad had put in his little cage
he was in the little cage till this evening when i cleaned his big cage and he was looking kinda sad in his little one so i thought maybe he was just tired of being there
but when i put him in his new clean cage he just...flopped

he was so lethargic
he wasn't responding much at all and was only moving a little bit, like he was trying to move but couldn't
i have him a little bit if applesauce and water with a syringe and put him back in the cage cuz he loves his little house
my brother came in a bit later to see how he was doing and took him out and..he couldn't even lift his head up and his breathing was really shallow
so i held him in my lap and pet him and he....he didn't last much longer after that

it's so weird cuz he was doing so good and we don't know what happened or what could have been wrong
all the vets are closed today and he wouldn't have made it to an emergency vet clinic, plus i dunno what they would have done
so....
goodbye little buddy <3
I'll miss you so much..