Enlarged Spleen with normal CBC

About a month ago, I started feeling incredibly run down. I thought I was getting the flu. After two days off work sleeping, I felt a little better. Then, about three weeks ago I started getting incredibly fatigued at the littlest of tasks. I saw my Dr and she said that my spleen was swollen. She did a pregnancy test ( negative ) a Mononucleosis test ( negative ) and a liver enzyme test ( normal ). I am still feeling fatigued, but dont know what the cause could be that my CBC came back normal, yet my spleen is enlarged as well as a negative on all possible culprits. Any suggestions? I dont have health insurance so each of these tests is costing me out of pocket. I am trying to eliminate the least likely of candidates to test for the most likely for cost efficiency.

[mammo]

They've ruled out all these?

What causes it?
A number of infections and diseases can contribute to an enlarged spleen, including:

Viral infections, such as mononucleosis
Bacterial infections, such as syphilis or an infection of your heart's inner lining (endocarditis)
Parasitic infections, such as malaria
Cirrhosis and other diseases affecting the liver
Various types of hemolytic anemia — a condition characterized by premature destruction of red blood cells
Blood cancers, such as leukemia and Hodgkin's disease
Metabolic disorders, such as Gaucher's disease and Niemann-Pick disease
Pressure on the veins in the spleen or liver or a blood clot in these veins
Mononucleosis,Syphilis,Endocarditis,Malaria,Cirrhosis,Leukemia,Hodgkin's lymphoma (Hodgkin's disease)Gaucher's disease.