chopsaw,

Thanks for your question.  I cannot think of any way that blood received from other people would have any effect on your sense of smell or cravings. 

During surgery, there are several different tubes that are placed, some of which could have been passed through your nose.  This could possibly cause a situation that might alter your sense of smell if your nasal passage is still blocked by swelling, bruising, or infection.  Cravings are from the brain itself and I see no relation at all. 

Hopefully this is all temporary, but if still concerned, a visit with your primary physician would be a good start, so that he can examine your nasal passages, pharynx (back of throat) and possibly run some routine blood tests. 

Best wishes.

Martin Cane, M.D.