Stress Fractures?

I've got about 50 lbs I'm looking to lose. I've been doing Turbo Fire regularly for a couple of months, but I'm modifying in order to not jump as much as Chalene does in the dvd. I figured I shouldn't push it too hard and risk blowing out a knee or something since I have so much weight to lose, you know?

Well, the last few workouts have been hellish. I'm getting stabbing, shooting pains in my lower legs. I thought they might just be shin splints, but after doing some internet research in an attempt to self diagnose, it sounds more like I have stress fractures. Before I go make a doc appt (that is my LAST resort), I thought I'd ask around and see if anyone had any experience with this problem.