HELP! My index page rankings dropped - now only shows subpages

I have about a 3 year old site. I just noticed that my index page rarely appears in the search results. Now, it just shows sub pages of my website.

What do you think happened? Do you think it's just a temporary?

 

no qualified comment possible without URL of your site !!!

 

Here is my site: http://www.insurancebyjohn.com

Any help would be greatly appreciated. Thank you

 

multiple possible reason

1.
http://validator.w3.org/check?verbose=1&uri=http://www.insurancebyjohn.com/

FATAL errors like
Unable to Determine Parse Mode!
and
No DOCTYPE found!

typically may make parsing / indexing by all major SE virtually impossible or incorrect, thus resulting in no or weak results!

if you have missing open or closing tags - that additionally may be a fatal error on top of all others

furthermore
if ever you made any major change on index page, then G puts your page back for up to 6 or more months. that happened to me for my index page which always ranked fine until I redesigned ALL page and dropped out with that page for about half year - during which time a subfolder page replaced a little more down the serps the original index-page

 

If your page rank goes down at once it's penalize by google.