Did you click on a link that was on that email ? Watch out, if the interface had a new layout for you, problably it's a scam ! Open a new broser window, TYPE the adress for google.com/adsense. and check again your name and password. CHANGE your password to a new one, and also check that nothing else has change, and the information there is YOUR info.
No, I visit AdSense through my GWT login, typed URLs, not links in emails. They had the same information in there that they have had for 10 years. Nothing but a new layout. To me, that is not the way you announce a new layout, trying to freak users out. They had a banner across the top telling me about how wonderful the improved new layout was. It makes no sense to word their notification that way.