WHERE DO ALL THESE BUGS COME FROM?

EVERYTIME IM IN MY ROOM ON THE COMPUTER AT 12-3 AM BUGS LITTLE AND BIG WILL COME FLYING AT MY SCREEN.I DONT KNOW WHERE THEY COME FROM I NEVER SEE THEM IN DAY ILL BE SITTIN AT MY COMPUTER AND LITTLE TINY FLIES WILL BE ON MY COMPUTER SCREEN AND JUST NOW A BIGG *** BUG CAME FULL SPEED AT MY SCREEN AND THEN GOT DECAPITATED BY THE CEILING FAN