Generally for roughly a week after the start of your periods, you are in what is called a 'safe period' from a contraceptive point of view. This means that because during this initial time your ovaries are not likely to ovulate, the chances of an accidental pregnancy are nearly nil. However if you have irregular cycles this period is very difficult to judge and hence highly unreliable.
Did you happen to use any morning after pill after you had sex? Earlier onset of menses, irregular bleeding etc. are known side effects of the morning after pill. In case of not being on any hormonal preparations, frequent periods or polymenorrhoea can be the result of a lot of clinical conditions such as thyroid abnormalities, uterine fibroids, weight fluctuations, stress etc.
This is something that you should not neglect as frequent periods may result in severe amounts of blood loss, sometimes even leading to anemia and hospital admissions. Contact your local doctor for a thorough evaluation.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.