I had the same problem. I thought it was just too much work and stress, but then the fatigue didn't go away. I started paying more attention to my diet and routine, but it didn't really help. Then I found https://ways2well.com/ where you can take a series of tests online and get recommendations from doctors. It turned out that I had minor hormonal imbalances and vitamin deficiencies that were affecting my well-being. After making adjustments, I felt much better. I advise you not to ignore it and to get a comprehensive health check-up, rather than just waiting for the fatigue to go away on its own.