[ElaineM]

Are there naturopathic doctors, internists who specialize in integrative medicine or nutritionists in your area? They are the best people who can help you determine where you are lacking nutritionally. They know which blood tests you may need or they may have other ways to determine what you need.
There are books about nutrition and some pretty decent online sources. If your white blood count is low various kinds of mushrooms may help, but you won't know that for sure until you take a CBC blood test. Generally speaking fruits and vegetables of all kinds help the white blood count which is also known as the immune system.