It is not unusual to have irregular periods when you first start having them, so most likely, you don’t have to do anything and your period will come back on its own over the next few months. However, you could also be working out enough to stop your normal cycle. That is fine; it will come back when you are not training so much. In the meantime, enjoy not having your periods. They are nothing but a pain, so if you get to skip a few, that’s lucky for you. The biggest problem with you is not knowing whether it is going to start soon or not, so you have to be prepared – always have pads with you and maybe even a change of underwear and pants in your backpack, just in case. Once your periods settle in and become more regular, you can plan for them, but for now, just be prepared all the time. And, as much as possible, don’t wear white.