Foot cramps?

I've been experiencing some pretty bad cramps underneath my foot ( has actually occurred on both feet..), it's not every day but when it occurs it tends to be when I'm stretching (stretches like child's pose can be quite the trigger). My boyfriend is convinced it's due to overtraining, but has something like this occurred to any of you? Based on the FB article I give enough time for each muscle group to rest between work out days ( routine goes like this; hiit+lower, cardio+upper, hiit+abs, hiit+lower, and lastly full upper body strength) in the week, plus I always add a yoga stretching video before my workouts. I'm not asking for a full on diagnosis, but rather some opinions and if this is a sign of overtraining? As far as I know my form is always good during workouts and I never lift too much or stretch until it hurts.