I am taking metformin 100 mg. twice a day. about 5 months ago I went through 8 weeks of chemo once a week and radiation 5 days a week for stage 4 cancer in the lymph nodes in the groin. during this time I only took the metformin on the day of and the day after chemo as my sugar stayed low except when the steroids drove it up. after the end of this treatment I went back on the metformin about two months ago I started having numbness in my feet. could this be caused by the metformin? I am also taking prescription potasiam, once a day, slow-mag 4 tablets a day vitamin b-6 melatoxim once a day .