Unable to concentrate, muscle spasms, light headedness?!

I've been getting muscle spasms for a while now!. At least thats what i think they are!. Every once in a while different muscles on my arm, chest, etc will begin to twitch for a minute or two then stop!. It doesn't hurt, it just feels odd!. That happens maybe twice a day!. And recently i haven't been able to concentrate in my classes and i've been extremely tired!. And when i stand up after sitting for a long time, my vision fades black and i feel dizzy for a couple of seconds (blood rush!?) And i've had random phases of depression!.!.!.Are any of these things related!? i got what i think are migraines (with aura, as far as i could figure out from wiki lol) last year too!. (maybe at most ten times in a year) But i haven;t gotten those for at least half a year now!. Any idea what could cause this!? Im only 16 so maybe that has something to do with it!? (and im male, that might be a factor)Www@Answer-Health@Com

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