guidance on "why am I appealing"

And I'm feeling so stressed. I have systemic lupus and fribromyalgia, PTSD. I receive standard rate on living allowance and mobility. I have been on this for 2 years. Unfortunately things got so bad last December I couldn't walk and was admitted to hospital. When I applied for pip and got it I was so grateful as I know it's very difficult to be awarded it first time round, and didn't want to risk appealing on mobility .I  applied for change of circumstances and since then it's been a nightmare. This has gone on for months. I gave them loads of medical evidence of changes. I'm now at the appeal stage to fill in the SSC1 form. 
I really need some guidance on the part of why am I appealing. And I have herd of people losing everything at the appeal so feeling a little frightened. My mum passed away a couple of months ago and helped me with all the forms and letters. If someone could help it would be very much appreciated. I have 2 weeks left to get it in on time. As I couldn't make my mind up ., through fear of losing everything.