Just because you are paranoid, it doesn’t mean they aren’t out to get you. Since yesterday not having a Google account is not going to stop your browsing history and web search behavior from getting recorded. But there’s hardly anything to worry about here, Google is only going to use that data to provide more relevant search results (and advertising, of course).
The last 180 days of your search are linked to an anonymous cookie and are taken into account when you make your next search. You can check out how much that improves the search engine accuracy by clicking the “View customizations” link on the top right of the search results page.
In case you are all too creeped about all that history recording, you can follow the instructions here to turn the personalized search off.
And check out the video demoing the positive sides of getting your search personalized: