For what it's worth...40 days is not a long time for your body to recover. Plateaus are basically your body re-adjusting to weight loss, and I've had some that lasted for 6 months at a time. Everyone is different. I suggest you hide your scale in a closet and stay away from it for an entire month. Measure yourself now, and again in a month as well. Stay on plan with your food, water and exercise and I'm willing to bet you will see a difference
With me, the whole time I was plateaud I continued to exercise, eat right, and drink my water. When the inches started to move again I dropped 9 of them in a 3 week period of time. Followed by a 3lb. drop on the scale the week after that! Losing weight is not for sissies. It's hard work and it takes determination, persistence, and above all..patience. Stay the course and it will happen for you.