Should I write an appeal letter? What should it include?

In October of this year, my primary physician put me off of work for 6 months because of acute anxiety, panic attacks and IBS that were prohibiting me from working. I am a teacher and had missed several days of work due to my anxiety. There were days when I had to run out of the classroom due to my IBS. My anxiety makes it difficult for me to leave the house and the IBS is so bad that I had to go to the ER for low potassium due to excessive diareaha. Overall, I am not in a mental state to be able to work in a classroom environment at this time. After receiving all of my doctor’s information regarding my mental state with detailed information about my health, M of O denied my claim, saying that I am able to work in my condition. They gave me the option to appeal, but what do I do? My husband became paralyzed from the waist down on Dec. 26th, further worsening my anxiety. Now we only receive disability through the state for my husband and are not making enough money to even pay rent. What do I do? My doctor offered to write an appeal letter on my behalf. What should it include? How can I get my disability claim approved?