www dot go4bagtrade dot com, i work on it. but a week ago, all rank drop much because my homepage disappear from serp instead of inner page.but still index.this happen to my other sites but often recovery in 3 days. i am afraid this site got penalty insteal of normal updated. i know some site homepage disapear from serp for a year or 1months. undoubtedly my homepage maybe never appear in serp again.what happen to my hompage? does google penalty this way often?