I Am A 76 Yr Old Male And I Seem

I am a 76 yr old male and I seem to have a low energy level most of the time. I tire very easily and most afternoons if I sit for a few minutes I will fall asleep. recent bloodwork shows everything in normal limits. I don't know how to describe my feelings to my dr other than what I said here. I do not think I should feel this way all the time.