Forum Moderators: phranque
The changes you made probably didn't cause the SE results changes.
Most likely, your sub pages are more relevant to the topics being searched. Just be sure to have proper navigation on all of your pages and you should benefit from this. And it saves people a click or two and should lead to more conversions (or actions).
Suggestion: If you're ranking well, don't complain about it!
Do you have a site map?
"Robert Charlton" asked a good question.
I doubt your page is not indexed. It just might be not too relevant for your targeted keywords/phrase.
Do a search in Google:
site:www.domain.com
and you should get all the indexed pages from your site.