hi its quite common to have anxieties of future.first thing why you are thinking this.if you are getting your periods regularly definitely you can become pregnant.if your periods are irregular consult the Dr to know cause of irregular periods like thyroid problems, polycystic ovaries, severe anemias . its also important to know your general status.dont worry there are so much advances in medicine which helps you depending upon your problem.if everything is fine with your periods and only this thought bothers you, meet the Dr for councilling. get rid of that thought from you now. Thank you Regards DR Vasundhara