Ive noticed this. when i play on my 3DS for hours and i feel okay. I use my PC for facebook and some other sh*t and im okay. But when i start playing games on my PC (my favourite way of gaming) and i get dizzy and my eyes get strained and i have a MASSIVE headache amd its just unbearable. But what the hell? I want to play! ive been playing on my PC for years and still this never happened before. i started noticing since 2 months ago.