Only First Page is Messed Up

Hi,

Yesterday I was making an entry when I accidentally hit a wrong key. I don’t know if it was a coincidence or not, but my front page was ruined. The main column is spread out across two columns instead of one, and my sidebar has been shoved down to the bottom, which is messing up my footer. Oddly though, the “older entries” pages look fine. I tried upgrading to 2.7.1, first through automatic, which didn’t work, then by manually uploading all of the new files onto my server except the content folder.

Any ideas on what could be messing up just my home page? I worked 17 hours coding other people’s pages yesterday, and my brain is shot. Thanks in advance.