@dorisena It sounds as if you are doing all of the right things. Your fatigue may simply be the same as mine — the frequent interruptions to sleep at night. Are you doing a lot? I actually find that if I get moving fairly soon after breakfast I do have more energy. The last time I went to my PCP I mentioned that I am tired a lot and often end up taking a nap in the afternoon. His response was "what's wrong with that?".
If your metabolism is slow maybe you need more activity to get it cranked up a bit, that's a possibility also. My husband is 83 and has always been much younger than his years but this past year he has found that he has slowed down a lot. He does still go to the gym three times a week and he works two days a week, but he often falls asleep in front of the TV at nighttime.