Thank you for your query.
It is not unusual for you to start your menstrual periods now. However you have to take adequate contraceptive
precautions. I suggest you do a urine pregnancy
test and consult your gynaecologist who will examine you and guide you. If required the doctor may order for an ultrasound
of lower abodmen.
I hope I have answered your query to your satisfaction.
Wishing you all the best.