based on the head spinning thing... have doctors investigated the possibility of Vertigo for the headaches and spinniness? I had Vertigo twice in the last 5 years, both times had me bedridden because I couldn't stand and my balance was pulling me down to the ground. Extremely disorienting 
. Unfortunately all you can do is some basic sitting up, turning your head, and sharply laying down exercises to try and knock whatever is out of place in the ear, back into place again. I actually struggle with constant nausea and digestive issues as well, so does my partner. We both have pretty extreme anxiety (I have diagnosed C-PTSD, extreme GAD, social anxiety, agoraphobia, extreme depression, OCD, BDD, and an eating disorder) and doctors have told us both we basically have chronic stress-related IBS. If your stress levels are bad enough your body can do a whole host of weird things in response. I've had joints spontaneously ache in my foot to the point I couldn't bear weight- as if my foot just broke itself overnight, my tongue has swelled up like I had an infection (but I didn't), I developed anemia (though that's partially because of the eating disorder), I've had foggy vision and shaking, inability to control my body temperature (another thing I noticed you had too), excessive sweating, and probably more XD.
If physical tests aren't showing much and you feel you may be suffering from a mental illness, definitely bring that up! You'd be surprised how relevant it can be if it's severe. I hope you get some answers, I'm in and out of the doctors on a bi-weekly basis myself so I know how frustrating it is to be a complex "mystery case"
<3.
I have an appointment for Thursday, though! The guy should get here that afternoon. 
. Tell him that a fellow fighter is hoping the best for him and to not give up until he gets answers!