Dear respected colleague, Impact Factor is always used for journals evaluation NOT for researcher evaluation, so are you asking about your h-index sir?
Presentation Journal Impact Factors, Researcher h-index, How to improve r...
If you are referring to your ResearchGate score, this will go down if you do not help other ResearchGaters as much this week as you did the previous week.
As Ian suggests, the RG score is an algorithm, not an absolute score. It ranks you with respect to everybody else on RG. You might think of it as where you stand with respect to the average. If many other people are more active than you, your relative position might go down a bit.
I have a fairly high RG score, but every now and then it drops back for a week or two, before beginning to work its way upward again. Part of that is everybody else, and part is how active I have been, personally, this week.