4 & 1/2 weeks flowering all leaves seem to be dying HELP!!

[crowlee]

YES I HAVE HAD IT IN THE SAME POT FOR AGES WHEN YOU TAKE THE PLANT OUT OF THE POT YOU CAN SEE THE ROOTS THERE IS NOT MUCH ROOM TO GROW ANYMORE WILL THIS AFFECT MY YEILD???? IT DOES NOT GET BONE DRY BETWEEN WATERING AND YES I HAVE A FAN ON IT FROM DAY1 EITHER 18/6 AND 12/12... OH AND IF THIS PESISTS WILL THE PLANT DIE IS IT THAT BAD???????