Just do a urine pregnancy test to see if you are pregnancy. Unprotected sex over one year causes pregnancy about 80% of the time. If you are not pregnant, consider yourself lucky and get on birth control pills to prevent a future pregnancy. Your periods are regular so you should have gotten a period on time, but sometimes the stress of losing one's virginity, the worry, etc. Causes the period to be late. Just get a pregnant test done ASAP. Hope it is negative. Pulllease use protection, even condoms give 90% protection, but birthcontrol pills give 99% protection. A baby changes your life forever, so does an abortion (emotionally).