Welcome!
You have a lot of good choices. A 10 mile commute is great, should get your heart rate up for a bit a couple times a day. Bicycling is good if you want to loose weight - you can burn a good amount of calories with little impact to your body. What you eat is the other side to loosing weight - but that's another thread. Don't think you're loosing the battle - maybe you just haven't figured out how to work with your body yet.
For clips, bars, racks, packs, bike styles, etc. there is an abundance of information on these forums. Read.
I'm 6'0" and ride a 56cm frame.