Suggest Treatment For Fatigue

About two years ago, I starting developing unexplained fatigue which I attributed to depression due to some family tragedies I was still dealing with. The fatigue grew worse over time until in late February, I was so weak I could not get out of bed. Slept for days. Felt horrible. Went to Dr and learned platelets and iron were low. In late April, I developed sudden, severe pain in one shoulder, then another. It moves around to different areas of my body. Seems to like my ankles, hands and wrists the best. Medium to severe pain with swelling and limited autonomy. 32 tubes of blood have been tested this year for various diseases, all negative. Fatigue better, but not gone. Iron, platelets, now Vitamin D low. Inflammation tests high. Help! I m 57-yr old female. Have never had anything like this.