I have a few different conditions and have been on PIP for years.
I have had to change jobs several times before I found the job I do now, which I can manage almost full time (5 days a week but longer lunch break).
I am currently having my best year in almost a decade and haven't been off sick for over a year now, but I am unable to do anything at the weekend except rest and recover from the previous week.
I have had to change to an automatic car as I can't drive a manual one anymore.
My husband does all the cleaning, cooking, laundry etc as I simply cannot do a job and housework.
I have to go to bed as soon as I get home from work, as I'm in a great deal of pain by then, so he does everything in the house.
I learned I have to spread my annual leave evenly throughout the year because if I don't, I end up off sick due to pain & exhaustion.
My advice would be to keep working because it actually keeps you from declining further due to inactivity. You really do need to 'use it or lose it' when it comes to physical activity when you have medical conditions which make exercise extremely difficult or impossible.
You may need to move jobs though to be able to keep working. Maybe a less physically demanding job, or a longer break at lunch to recover a bit? Maybe a job close to home so no long commute?
Becoming 'housebound' will usually result in you losing more and more of your current physical abilities, which will reduce both your mental and physical health long term.
It also reduces your pension etc, which is a concern. (Particularly if you haven't yet reached the 35 full years of paying into so that you actually qualify for the full old age pension at retirement age)
As for PIP, it's a long application form to fill in (but payments will be backdated to the application date if you're successful) which I'd advise you to fill in with help from Citizens Advice (or any disability services that offer to help with this) as you need to know the words/buzzwords to include and what the questions actually mean (You may say 'yes' to a question e.g Can you walk 200 meters, but unless you can do that regularly, repeatedly and with no pain and discomfort, the answer should be 'no')
There's lots of online sites that could help with filling in the form too, so have a look. Don't forget to keep a photocopy of your completed form and of any evidence you included e.g Dr letter, hospital letters etc.
Oh, and see if you can get a referral from your GP for an Occupational Therapy assessment too.(Some councils have a self referral available, look on your council's website) They come to your home and assess you and can arrange equipment for your home to help you (e.g I got a walking stick, wheelchair, grab handles, step for getting into the shower and handrails for my external steps)