I too had negative glucose tolerance test even though I felt dizzy and dropped a paper cup of water, etc. I felt better when using a diet for those with hypoglycemia. Ever try some chromium and support for adrenal cortex? Remember cortisol is a "glucocorticoid." something to investigate and learn.
What is the likelihood that you have that list of seemingly unrelated symptoms at such a young age and yet they are unrelated? Not good, right?
That was my experience too, but when ten years older. *Thankfully* I broke my leg without any contact or fall while just playing outdoor sports with young relatives under 10 yrs old. Before that I had fatigue, brain fog, mood and personality changes, poor memory, weak muscles that would get strained easily, frequent colds, cold hands, lethargy in the evenings, more introverted personality, eye floaters, low kidney blood test numbers, etc.
The broken leg led to the theory that I had lead toxicity. 1.5 years after I started oral detox--Cutler Protocol--my DEXA bone density improved 8% to borderline normal, kidney numbers normalized and have since improved much more, and many symptoms are much improved--fatigue, brain fog, cold hands, more outgoing and easy-going personality, rarely catch a cold or strain my back, memory is normal for my age, etc.
I'd be surprised if mercury is not at least a significant contributing factor. You list all of the most commonly reported symptoms in the heavy metal (HM) detox groups except mood/personality changes, frequent urination and sleep problems. The latter are related since people have to wake twice per night to urinate.
When I started detox my predetox urine, porphyrins and hair tests were either negative or just barely suspicious. My exposure to HMs ended years earlier and I had been taking antioxidants--vitamin C, E, selenium, etc. I had a decent job but needed three meds and a handful of supplements plus special diet. I'm now down to a child's dose of just one of the meds, generous doses of supplements and almost no dietary restrictions. I just have to be careful with caffeine but that runs in my family.
My point is that current testing for HMs is not good unless you had a major acute exposure in a chem factory accident, etc. There are many false negatives. Many people in the detox groups had tried so many other things for many years with little success and just decided to try detox.
There are many forms of HM detox, from big doses in an IV from a doctor, to green smoothies containing cilantro and chlorella. The latter knocked "Billy" on his butt as he described at one of the links above. There are plenty of reports from those who did not tolerate an IV or something else from one's doctor. Someone in my extended circle of friend warned me from his own bad experience. This is another. https://www.curezone.org/forums/am.asp?i=2255067
My health decline started when I was around your age. At that time there was no Internet. My six doctors over 15 years did not know what was wrong with me. i had to get lucky to come across Dr Mark Hyman on TV. He had been sicker than I was as a middle aged doctor. He says he went to ten other doctors before someone realized HMs were involved.
You are more fortunate than I was at your age. If indeed HMs are a major contributing factor in your health problems your life does not have to become messed up like mine was. Just don't make things worse by doing something rash. Do your homework before jumping in!
There are some good support groups at Yahoo and Facebook. The ones here are not very active.
Please update us. You are going to get major health gains over the next year or two if you do your homework and take reasonable action. Your symptom list is too consistent with what is seen in the detox groups, especially if you neglected to list a couple of the other common symptoms.