While I know this may sound silly, are you using a mountain bike? Is it a single speed bike? I am only asking because I commuted a few times on my old (and cheap) mountain bike to work which is a 5 mile trip. I am in Georgia and the hills are pretty intensive. I walked up pretty much every hill there was and it took me almost as long to bike as to walk! I bought a (very cheap) road bike and now rarely ever get off my bike. Hills- while I still feel them- are 100 times easier and certainly doable now.