When they did blood tests, did they check your Vitamin D and vitamin B12?
Those along with magnesium being low can have symptoms of fatigue and depressions, as well as other symptoms.
If your labs fell within 'normal range' doctors won't say anything is wrong. However, low normal can cause symptoms.
Vitamin D 25OH test should be above 50ng/mL
(Lab range is 30-100ng/mL)
Vitamin B12 above 500, but closer to 800 is better
RBC Magnesium optimum level is between 6.0-6.5mg/dL
Hmmmm.....there are many symptoms of depression, some of these symptoms could affect you physically.Your doctor could be right. It could also be stress. I have discovered that even when we are sleeping there are some issues that creep to surface and manage to penetrate our subconscious mind, leaving us even more restless than before we went to sleep. Perhaps a therapist could give you some useful tips to slow/stop your mind to maximize your hours of rest.
Paxiled suggested meditation. That has helped me quite a bit so I believe it is a great suggestion.
Anna
And do you exercise regularly?