Hi Traci! Your shoes could be a contributing factor along with other things.
Since its been a while for you, take your time and let your body get acclimated to the workout. If this is a new style to you, you are about to discover little tight and tender spots emerge all over your body within the next 48 hours, yikes! Good news is you will most likely never be as sore as the first time (unless of course you don't do the workout for a very long time again).
As for your feet, there is a lot of balance required during the kickbox combo's and the leg conditioning drills. This means that all of the little muscles and bones of your feet work overtime trying to help you maintain your balance. Combine that with the impact of the intensity blast section and your little tootsies have played a big role for you today.
Try a foot massage, maybe new shoes, a day or two off of activities that are "foot" demanding, and see how you feel.
Take Care!