From your description of symptoms, I would see a functional medicine doctor and get tested for GI infections; bacterial, fungal, parasitic. Also, adrenal, thyroid and reproductive hormones. There are a lot of good tests from labs like Genova, Great Plains, Doctors Data etc. that could pinpoint where the root cause of your problems may be. The good news is that you got a clean bill of health from the conventional docs but as is so often the case, there are underlying issues which they do not test for. This is where a good holistic physician could really help. Hope things improve for you. Best wishes.