If you are experiencing fatigue, look into allergies
I thought something was really wrong with me when I moved to Texas. I felt unbelievably tired all of the time. I read up on all kinds of maladies and syndromes. Nothing fit very well. A good summary of the conventional approach to unexpected fatigue is at webmd
In my case, it wasn’t a serious disease. I was getting a decent amount of exercise and sleep. Water turned out to be part of the problem, but the other was unexpected. Texas allergies make me feel really tired. I did not know that I was allergic to anything and when I had the sniffles in December, I assumed I had a cold. When the “cold” faded but my tiredness did not. I stuck it out for months feleing like I was packed in cotton. It turned out that a Zyrtec every day made a world of difference. Claritin works for others. Benadryl is the last resort because it has the drowsinesss side effect. Hoewever, my allergy fatigue was so profound that the drowsiness of benedryl was much less. On bad allergy days, I would take half a dose of benedryl and perk right up.
So, if you are fighting the doldrums, try some allergy meds along with the other suggestions on webmd. Check with your real-live doctor, drink more water, get more sleep and exercise, but try a little antihistamine too.