Hi Julianne
Yes it does appear that your condition is one of flat-footedness! At the moment your feet are not being used as well as they could be to support your body. Your muscles are most likely under-developed.
If you learn how to create the best alignment and support in your foot then you will actually go a long way to activating your feet and possibly part way or completely reversing or fixing this problem. You will also be helping prevent further possible issues with your back, hips, and so on… It’s all good news, but you really must pay attention to best alignment.
I had a similar issue with fallen arches (pronation) and through a regular practice based on PRECISION techniques (the ones I teach here and in my writings, emails, books etc) I have healed that problem.
Anyway, a great place to start is with my free video called Great Posture From The Ground Up! The link is to the page with all the free videos. Find it half way down that page.
Let me know how you go!
Namaste
Gabrielle 
