This is Google Penalties or no ?

there is another way

install a redirect plugin in your wordpress blog
now you will need an old site map. If you dont have that do site:yoursite.com in google and find all indexed pages
than redirect all old url to your new urls

actually this is a must, for changing url structure for a site. otherwise google bot will not always know that your new url is actually ur old url.
plus you will get to keeep the linkjuice you created in earlier url's

Bad idea- people dont understand how transforming a site and not keeping the URL structure and content structure can have serious consequences.

This is because of the switch.

I installed 404 Redirection plugin for my wordpress , this is big problem , but now i should finde best way to recover my ranks , i submit my sitemap

in google webmaster tools and all url's indexed now .