Suffusion has its own support here:
http://aquoid.com/forum/
Then what is this forum for?
These forums support WP Core, plugins and themes from this site — and Suffusion certainly qualifies – so it is supported here. But a few (very dedicated) developers have opted to also create their own forums — where they can generally provide more specific and often faster help than might happen here. For example, I’m not familiar with Suffusion, so I cannot answer your question. You’re more than welcome to post here, and Sayontan does check these forums, so you’ll likely get a reply from him here at some point.
You have probably opted to customize the look and feel of the navigation bars from Suffusion Options → Skinning → Navigation Bar Below Header → Default or custom. If you switch it back to “Theme styles” you will get back your original look.
