Help with my weight loss plateau?!?

I am also on P90X , but 7th week. I am training for marathon, so I am working on lean with some more double up, plus 40 - 50 KM running every week. I almost drained every day. (20 hours plus weekly workout). I think if you change your workout routine, you better change your diet as well. Did you follow the menu of P90x? I dont drop by number, but dressing size. did you? keep going, you have a very very good start, i think just wait a bit you will start losing again.