HELP!!!!!! am i getting the right amount of exercise?

I personally think your doing great! But if your having chest pains, sit out for a while if it happens while your running or whatever and go light if you feel pain before. As for the skipped periods, when you exercise frequently, your menstrual cycle, as I like to call it, goes on a break. Especially since your a runner, your lower body is moving ALL THE TIME, so it's kind of like you don't have the time. In school volleyball, our work-outs were intense and while the season was going on, I hadn't had my period. I actually skipped for 5 months, but then it eventually came back. It's completely normal for athletes. Great job on work-outs by the way! Not a lot of people ENJOY working out.....it's addressed more as a chore than a blessing to have the ability to move and function your body that some people just don't have.