Hi,
I was diagnosed with leukaemia (CML) in 2001, had Bone Marrow transplant in 2002. Permanent fatigue and enlarged spleen were amongst the symptoms that I had prior to my treatment. However, having enlarged spleen (splenomegaly) does not necessarily mean that you have leukaemia, it can be caused by other health related problems as well.
My advice to you is to see a Doctor or a Haematologist; they will be able to tell you what causes your symptoms. Do not wait until it is too late, leukaemia can be treated if detected at an early stage.