I am extremely lethargic and I have a history of aml leukemia and I have not had my blood levels checked in two years, should I be concerned?!

See below... Considering your previous diagnosis of aml, periodic check-ups are strongly recommended, especially if symptoms are present. That is not to say that based only on your lethargy you should directly jump of the conclusion that your leukemia is back, but consulting with your physician and getting a CBC is probably a good idea.
CBC. There are many possible causes for lethargy that do not involve a recurrence of leukemia (infection, depression, sleep apnea, etc.). However, if the lethargy persists or is accompanied by symptoms such as petechiae, new bruising, bleeding, or bone pain, i would definitely see a health care provider. If you are concerned, a simple CBC (complete blood count) would be a reasonable place to start.