Were your posts of good quality? It is possible that Google thought they were spam. This certainly seems the case, since the consistency of your posting is the only thing that changed.
Also, If you post less then usual, let's say you have 8 posts a day and you decrease it to 2 posts a day, it will affect your traffic too. I guess the only thing that we should do is trying to get more targeted link to our site and wait for Google's mercy to revive the traffic!