I feel like this every time I get ill. Somehow the house falls to absolute bits within a couple of days, every single time.
Washing on first, that will take a while to process so just keep going on with it bit by bit.
Generally speaking, I'd do tidying before cleaning, and cleaning before declutter.
Aim for a first pass through where everything is "good enough" tidy everywhere before you go back room by room for dusting/hoovering/cleaning etc (although I do wipe down surfaces in the kitchen at this stage). Can wipe the sinks and bleach the loos, but if the bathrooms are already needing cleaned another couple of days will make no difference.
Then go room by room to clean starting with living space, kitchen, hallways, then bedrooms. I do bathrooms last.
Once everything is clean and tidy it takes a lot less time to keep them that way, and it's only then that I have the time/energy to tackle decluttering.
And most importantly, make sure you have nice biscuits and tea waiting :)
Good luck!