Neurological - Foggy And Blocked / Fatigue / Drowsiness?

Since this June I have been to so many places from my physician’s office to the ER and everywhere in-between. Nobody can find what's wrong with me. I’ve had two neurologists give up on me and one who (after running a bunch of tests) say I have anxious tendencies. I had every test possible ran on me and they all came back normal. Actually on paper I’m as healthy as can be. That's the problem, all my test results are perfect so people think there’s nothing wrong. It’s hard to explain what I feel like. My thoughts feel foggy and blocked, I’ve become very forgetful and academically I’m struggling. That is only the mental portion unfortunately. Physically I have muscle cramps, fatigue/drowsiness, disorientation, trembling, tingling, and clumsy-ness. I’ve had a spinal tap, loads of blood tests, two EEGs, MRIs, and been evaluated by six different doctors. Every blood test you could think of has been ran on me. Including heavy metals, vitamin b-12, Lymes, lupus, hormones, blood sugar… there are loads more but I can’t remember them all. I’m worried most about the cognitive aspect of my problem. Its very debilitating. Some days are better than others, and some are worse. Today was one of the bad days. I can’t  stay focused or have clear thoughts. When I talk I don’t make much sense. I say words that don’t fit into context, have a very hard time finding words, and as a result, can’t keep up a conversation very well. I try my hardest to overcome these problems but I don’t think its a matter of how much effort I put forth. Some days I just can not think straight. I even have problems understanding what people say to me. I understand the words, but the meaning of what’s said just doesn’t get through. Like I said, some days are better than others. The memory isn’t isolated to only short-term or the forming of new memories. I have a hard time remembering things that happened long ago as well as what happened five minutes ago. The things I remember are fragments and very inconsistent. I was stating to think that my problem could be low magnesium or something like that which was overlooked. From my understanding of a mangesium deficiency. It takes a long time for you to become deficient. This makes sense because this problem didn’t just stat overnight, I’ve actually been having this problem since February. I’ve been blowing off the symptoms as lack of sleep or just being tired but it built up to the point that I realized something was truly wrong. So magnesium might make sense, maybe. I’m just guessing at this point though.

So, what do you think? If you have any ideas what the problem could be please let me know. As I said before, I’ve had my heavy metals, Lymes, hormones, vitamin b-12, lupus, csf (spinal tap), and blood sugar checked. I’ve also had a complete metabolic panel ran, a complete hormonal panel, and complete nutritional panel checked. I think an allergist might be a good idea but I’m not sure. I guess its worth a shot.

 Here’s some info about me. I’m 17 years old, male, 5’9’’ and weigh 128 LBs. The problem is constant 24/7, never goes away.