Hi,
I sympathise with you. Depression does this. It's a tough one to overcome.
Don't overwhelm yourself. Don't try and do it all at once. Because even if you do, you'll feel 'I did that already and really resent having to do it again in two weeks time.
Instead, set up small chunks of time each day to do some jobs that make a difference. It's really great you keep your kitchen clean and tidy. That's the best start.
Next, do the same for your bathroom.
First job: get some strong bin bags, some wipes (Wilkos are good and cheap for wipes if you have one near) and a large box of any sort.
Put anything that doesn't belong in the bathroom in the hallway outside.
Put all toiletries etc into the box, except ones that have less than 1 cm of product left in them.
Chuck away old toothbrushes (keep one ot do the tiles if you want but not 5, old make up, any rubbish and all except two of the old plastic bottles with 1/2 cm of shampoo or bath gel in them.
Add a bit of water to each of the two you keep. Chuck one down the loo and scrub the loo with it. Rinse one around the bath and scrub the bath with it. You can use an old facecloth or sponge to clean them if you throw it away afterwards, or a cleaning spnge or cloth if you have one.
Rub taps, windows and mirrors. You can use glass/window spray cleaner if you like, or white vinegar. Or just rub with a damp cloth or wipe and then polish with a dry towel.
Finish by cleaning the surfaces and floor with wipes and chucking the wipes.
Then stop. That's enough for one day. Now you have two rooms in good order - kitchen and bathroom.
Get your teens to put away or chuck away stuff now on the landing that should never have been in the bathroom.
Then have a small reward - cup of tea and watch a comedy or glass of wine in a sunny spot - whatever you like. Don't do too much.
I really recommend Flylady. She helps you get started on a routine. She understands you should never blitz a place or you'll think you've 'done' it and not want to do it again. She gets you into easy, manageable habits.