What Causes Constant Tiredness And Drowsiness?

My wife and I have been excessively tired for the past two weeks. It is an overwhelming desire/need to sleep especially after meals. Sleep does not seem helpful as after sleeping we do not feel rested. We both have burning eyes as well right before we feel the need to sleep. We are both experiencing low energy levels and it seems like doing anything is a chore. We are both retired, I am 63 y/o and she is 58. Do you have any ideas?