Ah, well that's good to hear you've caught the bug
It's a great feeling when you just change a couple things in your habits and can have such an impact! Hopefully you didn't drive too much around Chicago, though. I know the traffic around here can kill your mileage quicker than anything. Have you looked into the 60 mods you can do for better mileage on the forums? It's a great read, and really covers a lot of things you can do!
As a word of warning, please be careful with drafting vehicles. It can reap you great mileage, but it's not worth risking your car or your life over! So please be cautious with that