Hey dude, your registration date was in November 26, 2017. So by the next week you should start earning more activity points due to the restriction to a 2 weeks period.
The activity has been very very ...... veeeery explained here in the forum, here it goes the explanation from @theymos:
The activity number is determined in this way:
time = number of two-week periods in which you've posted since your registration
activity = min(time * 14, posts)
Rough summary of what this means: If you post once per day on average, then you will eventually get the maximum number of activity points that you can get. Posting more than once per day on average is useless for increasing activity. The maximum number of activity points you can get is 1 per day, but your activity score only updates every two weeks. Therefore, it will take about 100 days to get 100 activity if you post once per day on average.
Activity is updated every hour.
