New Gmail interface. A shock at first but actually pretty sweet.
If you want the old view, you can certainly make that happenhttp://lifehacker.com/how-to-get-the-old-non-tabbed-gmail-inbox-back-510493753
I would encourage you to give the new one a chance though. It has certainly kept my inbox sorted and filed quite nicely. Now I see "real" email in one tab, and other clutter under other tabs.
Regardless, you can get it back to the way you want it, pretty easily.