Woah where did my HD go?

Ok accidentally clicked on "guest account" to log into my mac...was taking a while to log in so i walked away, came back a minute later and i was greeted with my normal login list again, my usual acc, and the guest user, this time i clicked on the correct one and when it started up i now have a VERY simple desktop, std snow leopard desktop (not my normal desktop pic) and cant see any HD.

Ive been using macs for decades.. what the heck have i done here? repeated restarts and logins never get me back to me usual user acc?... errrm panic kicking in