What Causes Swelling In The Feet While Suffering From Diabetes?

Doctor, For five years now I have been given Disability Rating with Diabetes Type-2 from service in Vietnam. I say hello to my feet every day as precautionary procedure but about four weeks ago, suddenly first my left foot swelled up then the next day the Right foot as well. I have had blood tests done with non-VA clinic here in Manila (since I am not covered fully except for service-connected issues). I have tested as anaemic and with low B12 levels (*However, B12 was last tested just slightly above the low end.) My feet were swollen for more than a week, though Furosemide had to be taken *about 7 days. I will have VA Clinic Dr. checkup in August, however I am concerned because though having two B12 shots now, there is still some swelling. Test results were enough for the Doctor to tell me that my kidneys and heart were in fine shape. Problem may be with liver. Any links to articles on Agent Orange, anaemia, B12, and swollen feet inter-relationship would be appreciated. Thank you very much.