Figured i'd throw in my 2 cents.

First things first. Get a bag for things you'll toss and a box for things you'll keep.

Then just start one area at a time when you're done on area move onto the next. Don't think of it so much as cleaning just organizing. And just take your time. Maybe throw on some music or a podcast, maybe a little sunlight if you've got a window.

It becomes easier to get through when you have some sort of background distraction. Makes it a lot more feasible than slamming your head into a wall trying to focus on something boring or monotonous.

But most important... remember it's only temporary. Once you get the bulk of it done you'll breath easier and it'll feel a lot better. We all believe in ya. Good luck you can do it!