In 2007 I had crushing fatigue. Found out I had mild sleep apnea and low T. I fixed the apnea and my T level has been better (also with lifestyle changes)
Starting in June I got that awful fatigue again. Needed loads caffeine to get thru the day. I could not figure out what was causing it, Did my T drop again and why.
Then I remembered reading on this site about painkillers causing T to crash. Then it hit me, back in May I had shoulder surgery and was told to take Percocet to minimize pain while stretching the shoulder. I was only taking one pill per day (for seven weeks). I stopped taking them three weeks ago and I now feel much better.