How long does the plateau usually last when working out?

I'm now in week 5 of the P90X program. Thus far, I've lost 25 pounds. I feel great except I didn't lose any weight last week when I weighed myself on the scale. I went from 245 to 220, and my target goal is 195. Is this plateau only temporary and will my body kick back into gear again? The reason I'm asking is because I did the Body-for-Life challenge five years ago, and I didn't get the miraculous results that the people in those ads did though I followed the program down to the T. I have learned from my mistakes then, and I don't eat any complex carbs after 2 p.m. During my binge day, I've even restricted it down to one meal in lieu of an entire day. Will this wall I've hit soon disappear, so I can continue onward with my journey without getting discouraged again?