With Myelofibrosis I have good days and bad days - is this normal?

I am 82 years old and have myelofibrosis. Some days I feel okay, but on other days I am wiped out, lethargic, low energy, wobbly, and generally feel unstable and weak. So far, the good days still outnumber the bad days. Do other people with myelofibrosis experience these swings in how they feel?