AdSense Code gone wrong!!

Hello! Help!! I was trying to put AdSense code into sidebar.php – I tried it in several pages in that document but then pulled it out. I also tried the Easy AdSense Lite widget. Nothing showed up in the sidebar again. However, now there are three blank squares muscled into the actual first three posts (one for each post – I think like the 3 squares of ads that are supposed to show up). Please help!! I want my posts back looking normally!! Thanks.
http://www.schoolnuggets.com