Plateau or done losing??

I hit a plateau (I hope) in mid-February (6 months out) and hadn't lost a single pound until this week.  I have lost 100 (well, now 103) pounds and then, nothing.  In April, I started walking my butt off, trying to get something going, but nothing until this week.  I am not sure if the few lbs lost this week are real or a fluke, like water loss or something. 

Did this happen to anyone else?  Could I possibly be done losing?  I still have a lot of weight to lose - I would still like to lose at least another 50 pounds.  Any suggestions?

Thanks.

Pam 

Pam go back to the Basics! and do the 5 day pouch test http://www.5daypouchtest.com/plan/theplan.html