I have to agree with everyone here that has posted. [B]DO NOT HAVE AN AMPUTATION. You are just trading pain for pain. I also agree that it seems to me that you are not on enough medications at this point. The same medications that work for me may or may not work for you. But you should be on a nerve pain medication, regular pain medication, extended pain medication, possibly a muscle relaxor and antidepressent.
I remember feeling that I just wanted my foot cut off and how bad the pain was. Now my pain is tolerable with the right medications. Please check into adding additional medications.
It may help you to check out the RSDSA.org website. There is a list of medications commonly used to treat RSD.