Hi
Enlarged red blood cells is called as macrocytosis. It is caused by a lot of factors such as deficiency of vitamin B12 or folic acid, liver disease, alcoholism, medications (anti cancer drugs) etc.
Do write in if you need more information.
Regards
Could it be a sleeping medication such as zopiclone, I have been tested for vitamin deficiancies and don't have those, I never drink any alcohol but I do take topriamate for seizures and zopiclone for sleep.I