at the risk of annoying everyone here on the vegetarian support forum i would suggest that IF you are a blood type O then you really should consider the "eat right for your type" concepts. more info here.
if you are a blood type A then i would suggest that you still take your doctors advice but also look into doing lots of wheatgrass as that is the ultimate blood tonifier and cleanser. type A's are natural born vegetarians.
also the Webmaster - Spirit - was a vegetarian who now eats meat due to his being a type O. look into it.