Why is my body revolting?

I've been on Weight Watchers for 4 months... and I swear for the last month my body has been revolting against all my efforts....I have stuck to the plan the only thing that has changed is that I don't wait to exercise everyday or walk on the treadmill for 2 1/2 hours on Saturdays and Sundays...... I have run out of steam! The most I lost is 20.4 lbs, currently at 19 lbs lost..... I really dread weigh ins...... I did talk to the leader and she suggested that I use 1/2 of my exercise points that maybe my body is going in to starvation mode.... I don't know about that but I have eaten a couple of my exercise points. I selected my goal weight..... the max for my height.....I didn't realize that once you achieve Lifetime membership that you can go under your goal weight just not 2 lbs over it. So I'm about 2 lb's away from goal.... that is what I need to focus on! I am loving ATS belly dancing (American Tribal Style) an Instructor must have been trained/certified by Fat Chance Belly Dance ( Carolina N. the creator of ATS) to call yourself an ATS instructor. The ATS classes are taught at a Rec Center and there is currently 3 weeks in between sessions, my goal is to advance to the next level of class by November..... so I'm going to pay for private lessons..... I need the help... I'm nervous about the one on one factor....all eyes on me and what I'm doing in correctly...... I just have to keep my eyes on the goal.... I went to support Tribal Evolution my instructors troupe at Yaa Halla Y'all......it was exciting to see them perform......last year at YAY was the first time and the fire was starting in me! d