Thanks for the advice.
I've actually been to a physical therapist for my feet before, so I know the exercises to do to strengthen them (as much as possible anyway). I also have professionally made insoles (regular wear & for exercise), which wasn't cheap, but it was worth it for the help it has provided.
I think my body is just telling me to give it a rest. I guess I'm stubborn and didn't want to "give-up" on a day of exercise, especially since I realllllllllllly want to achieve my weight loss goals. However, if I injure myself it will really put a damper on trying to lose weight.
As the day has went on my knee/arch/ankle pain has lessened, so I am sure I'll be good as new to start back up tomorrow.