I don't know a single non-Greek Gator who feels like they missed out. Whatever happens, you're going to have a great time in Gainesville. Seriously. There are ways to form those bonds without a letter shirt!
I believe UF has an upperclassman quota, but there's no guarantees, of course, that you'll get a bid just because of the upperclass quota. However, I hope that reassures you that if a chapter wants to pledge a qualified upperclassman, they do have opportunities. There are also opportunities for Spring recruitment if you're unmatched in the fall.
I know it is all a bit nerve wracking and exciting, but continue to read about recruitment on Greek Chat, keep a low profile online, and keep a very open mind about accepting membership in any of the chapters at your school. Your options may be limited as an upperclassman rushing at an SEC school, so if you really want to join a sorority, be happy with a bid to any of them and make the most of your experience.
ETA: Any chance you'd transfer this fall? Or why not rush at your present school and stay there?