When you were drinking heavy, your body's preferred form of nutrition became alcohol. It is the easiest substance to metabolize there is and your system just jettisoned the rest. All of the good food you were eating went unused. Now that your GI system is learning that it once again must convert your food for your body's energy source, it is shifting gears. Listen to your Doc of course, but I don't think there is anything to worry about while your body learns to function normally again.