Sudden lost of congnitive abilities.

Sir I was a topper in my class suddenly I got concentration,focus attention problem If someone is talkng to me them I won't get a word even if I tried so hard..words just go like that..I'm even unable to understand time(if some one say 10 o clock they my brains thinks how should I understand it..i shld understand as after 9 or befor 11..my brain thinks this way) If I read anything am an able to process anything again coming to first and reading still unable to get a word or its meaning...and even am unable to get if someone ask "had ur dinner" Unable to process it properly.... ITS VERY HARD FOR ME TO SLEEP EVEN THOUGH I SLEEP I WILL NOT FEEL FRESH in the morning... THE MAIN PROBLME IS FOR NEARLY 3-4 YEARS I WAS IN FULL IMAGINATION WORLD WHERE I HERO KIND OF IMAGINATIONS ETC.. Becoz of this my brain Berger's used to feel hard and ache too.. I think this is the reason for my health issue Am unable to talk to ppl around me Please rply what's my problem is PLEASE RPLY DOC