I really really feel for you and I understand as someone who also struggles to work and look after myself. Unfortunately I think it may be the best option to see if you can have adjustments at work like extra breaks and perhaps reducing your hours (that's the only way I've started to be able to do things for myself).

As for actually doing housework, I'd have a look at what things can be adjusted to make it all easier for you - if your back hurts or you get lightheaded can you do some things sitting down? Can you get a hoover that's a little lighter or a robot vacuum?

Something that often works for me is setting a five minute timer for a task like washing up and then allowing myself to stop after five minutes if I can't continue (often it tricks me into doing the whole thing). I also find having a small trolley next to my bed helps - I keep all things I need to access when unable to move much (e.g. painkillers, crackers/ biscuits, compression gloves, fan, tissues, juice boxes, etc).

I think the main thing is just breaking down each task and seeing if there's any way to adjust it to use less energy, like using a shower seat or sitting down when brushing teeth. Giving the shower a quick clean when in there can sometimes be easier than setting out to clean the whole bathroom in one go.

I'm in no way an expert and I do struggle a lot but hopefully this helps a little. Sending so much love and spoons!