If you follow your progress in the ranking of a group  you belong, keep in mind that the data of the ranking of groups are updated daily with the data of your activity of the last 7 days.

 It is not a total of your account so don't worry because you're not loosing calories, kms or points. 

Therefore your position and data that you will see in the ranking will increase or decrease depending on what you did the last 7 days.