Can stress or depression cause weak muscles and extreme fatigue?

Hello, and thank you for your question. (Keep in mind that an in-person consultation is necessary for the best advice.) Although the term "breast implant illness" has been used by patients (and some physicians) for several years, "breast implant illness" is a diagnosis that has not yet been accepted by the medical community. The condition itself is poorly-defined, and its symptoms vague and variable. That is not to say that patients aren't experiencing symptoms. The evidence is just limited as to whether the symptoms are due to breast implants. 
Fatigue, weakness, and poor sleep can have a number of causes. If you believe that your symptoms may be due to stress or depression, you should consider visiting a mental health professional who can evaluate you in-person, address your concerns, and (possibly) develop a plan of care. Best of luck!
Matthew A. DelMauro, M.D.

Stress and depression can cause a whole host of mental and physical problems. I would suggest also being tested for food allergies, especially to wheat, dairy, eggs, soy , and corn.