Struggling with work


first post on here for me ,

was diagnosed with pa 2 years ago after years of back pain , Ankylosing spondylitis

ive missed time in work due to back pain and unfortunately it’s just gone again, I know it’s gonna be like this in pain and struggling with mobility for next week or so , I’m at the verge of leaving my employment due to this, I can’t keep letting my employer down and I feel like the work I do is making my condition worse as it involves a lot of walking lifting, I’m confused what best to do and what benefits I could claim if I did finish work , has anyone been in the same position and can offer any advice?

thanks for any help