You may want to see a sleep specialist if you've had problems with sleeping for an extended amount of time.

Have you seen an endocrinologist? Or someone who can do a test to check your thyroid? I think that a physical would help you as much as a mental check for the depression. Remember that physical and mental pain are expressed the same way in the body. If you can isolate symptoms you're experiencing, and write them down, it could benefit you greatly because the doctors will have a better idea of what you're experiencing.

Sometimes physical ailments can mask themselves as symptoms of depression or become depression. I'm sorry about your husband, too.