Have you visited or posted on our SSI & SSDI forum?
Also the sticky threads up above it may have tips on how to get by while waiting.
http://neurotalk.psychcentral.com/forum28.html
Search out all the county and state resources you can, food co-ops?, or food share?, join a church?- that can often be a good source of help & support.
Another thing is look for "frugal living" info websites - tips on how to make do and get by.