Reassessment f2f date received

hello I’m new here, and need some help. I suffer with severe fibromyalgia, chronic fatigue, Ankylosing spondilitis. Degenerative disc disease, sleep apnoea and I have mental health issues. I’m 34, married with two small children. My husband is my carer 
I was awarded standard for both parts of PIP nearly 3 years ago. This was before my AS and OSA were diagnosed. I scored 8 points and 10 points for mobility. I put in a MR for mobility and wasnt awarded it. I didn’t appeal as I didn’t have the physical or mental strength 
my conditions have no cure. They can try and improve my quality of life but thingswill only get worse for me. 
i am extremely anxious about my f2f the whole thing fills me with severe anxiety - a stranger in my home.. the grilling, the risk if losing my award, the assessor telling lies.
i am worse than I was last time and indicated on my reassessment form the areas things have declined in due to my deteriorating health. I am plagued with flare after flare, I am in pain every minute of every day despite a belly full of pills, I have issues with my arms and hands due to nerve issues in my neck. I am dizzy and wobbly all the time, my mobility is poor due to balance issues, leg weakness, dizziness. I can’t walk without pain and discomfort as it’s there all the time, walking more than a few metres makes it worse. Standing can be hard due to the same. I spend a lot of time laid down. My ability to talk to people is hard, I get lost in conversation, forget things, have noise adversion and find talking exhausting. I get my words muddled and have difficulty explaining things. I am socially isolated because of my difficulties. I have issues and difficulties with nearly all aspects of DL too.
I worry il get tripped up by the assessor and not awarded what I think I should be entitled too. Any tips of support for me? Getting PIP allows us to pay for extra help, it also passports us for entitlement for financial help so my husband can stay home to care for me. Without pip none of this would be possible 

Sorry for long post.