First work coach soon am a bit anxious about it

Am on daily pip and have been for more than 8 years ( now im 62 ) and on esa for more than 8 years and now Universal credit , I have two autoimmune conditions neither curable and lifelong , I struggle to do any normal day to day tasks , cleaning, tidying , and to function , have so many problems each day is like navigating the crystal maze ! I am anxious I will have someone pushing me with ridiculously unrealistic and unachievable tasks as some work coaches are appallingly dismissive , stress will hugely effect both of my conditions badly ( Rheumatoid Arthritis and Hashimotis disease ) . What do I say if im asked to do things totally too much for me ? which could be small things in my case . I don't want to say yes to my claimant commitments just because they seem all to her ! Many thanks . P.s I have telephone calls only and can't and don't have a online journal .

Thank you David so much , I will indeed let you know how I get on .