this is exactly how i am i cant concentrate on anything apart from whatever stupid obsession my brain is tuned into at the time. everything else goes out the window. i did badly at school probably because of this (but i fluked good grades from my exams so i passed, although since i KNOW i had no idea what i was doing i failed really) and wasnt aloud to drive because i couldnt keep my attention on it and kept thinking about stupid stupid crap or talking to my instructor about some rubbish or another and i dont seem to be able to multitask all that well (everyone else can drive and talk at the same time)

i hope you can figure out what it is and how to fix it, im guessing anxiety since that comes up a lot...