Harlequinn not eating/lethargic - please help, serious!

Went out to my pair of buns last night to 'tuck them in' (put the cover over their hutch) and both were alert and well.
Gone out this morning to give them their food/fresh water and Harlequinn - my boy @ 1yr 10mnths was in his sleeping quarters all huddled up. I gave him a fuss and he didn't really respond. He is the type of bunny who craves human affection/attention and loves his food times - infact he usually sits waiting for breakfast in the morning with big dopey "give me more Mummy" eyes
I've had him indoors for an hour now, as I thought it could be the cold but he's still lethargic/not eating/drinking or pooping - tried all his favourites: curly kale, dandelion docks, banana, apple, cucumber.
I know it's serious if bunnies stop eating, my vets open at 9.30, but I'm wondering what I can do in the next 40mins
I've seen him like this before when he had 'the op' and refused to eat etc and know he's now doing the same. But this time I can think of no reason why he's in pain/feeling unwell.
I'm really worried.... PLEASE advise me!!

What's more Sakura his wifey is very much trying to steal my attention - she's headbutting me, all over me, all over him, darting around -- she's the total opposite of Quinn and isn't really a cuddly bun. It's as if she knows...

My advice would be to go down to your vets so that you arrive before 9.30 because he sounds very ill. That way he will get treatment ASAP. It's a bit cheeky, but they should be ok with it because it's an animal in need of vet attention.

I'd also keep him warm.