Hi Anuja,
This is not solution it clarification of your question. :)
This was not due to down voted your artilces/answers/tips etc.
I lost my points around 15000 within 16 hours :(.
It's because off "The main rep point adjustment seems to be around
the download points for article attachments. the points were changed from 5 to 1 the other day, and chris was doing the recalc last night." for more information please see the following thread.
Surprisingly!!! I lost 15000 reputation point within 16 hours[
^] :)