Do I have to return to work despite my issues if I can still appeal the denial?

I have been on short term California disability for almost a year. I applied for LTD and submitted all their required documents and my doctors submitted their reports, my employer also submitted all the required paper work. The company denied me due to not enough medical information. I am suppose to return to work in one month or I will lose my job. I have a numb leg and foot due to a herniated disk, as well as weakness in my legs and thighs. I also have periodic pain. My biggest issue is the weakness and numbness which makes my gate unstable. They have an MRI which shows the issues with my back. I was wondering if I have to return to work despite my issues if I can still appeal the denial. If I did win, they would at least owe me from may to Feb. the difference between my STD and what LTD pays.