Rat suddenly very lethargic

My rat Ahab (~1 y/o) began acting very lethargic & weak, when I pick him up he is limp and slow to react. Currently he is laying in the corner of his cage wrapped in an old t shirt
He'll accept water, but isn't very interested in any food

Just yesterday he was acting happy, healthy and active.

I have no clue what it could be, except that yesterday when I let him run around my room he found some chewing gum I left out, but I took it away before he could eat too much. Could that be it?

His cage mate is perfectly fine and full of energy

Help please! I'm very worried

I would find an emergency vet if you cannot get him to your's. Perhaps he has a blockage

The only vet close to me that sees rats is closed for the day, I'm taking him tomorrow for sure but I was hoping there is something I can do in the mean time

If the gum is causing a blockage I wouldn't force him to eat any food. Can you tell if he's pooping/urinating? Can you feel anything in his tummy?

He isn't pooping, not sure if he's urinating. I can't feel anything, but then again I'm not really sure what I should be feeling for

He could also have had a stroke, or eaten something poisonous to him when he was roaming (I'm not too worried about the gum.) I hope he does OK and your vet can figure out what is going on. Good luck!