When I started commuting I had a rack and one pannier/tote bag and a bike that was 16 years old, granted it was a Trek which last forever, I have a very short commute but live in the snow and also grocery shop and everything else by bike. I have killer hills and 6200 feet of altitiude so the short commute is a blessing. 24 months later I have turned the Trek into an Xtracycle (look at the website and dream) It took me 4 months to save for the conversion. I now have 3 bikes and more gear than you can imagine best part of commuting.
Take it slow and dont give up, eventually the pride you feel when people stop asking "did you ride today?" will be worth it. They stopped asking and just started assuming after 2 years.
Also, give yourself a break, if you just cant do it one day, dont. The worse thing that could happen is that this becomes a chore and you hate it. The next day try again.
Good luck and welcome to the commuters