What Causes Delayed Periods With Vomiting And Abdominal Pain?

Hi, I am 25 years old.Last month in July my periods were irregular.I got down on 5th july & got over with my periods on 7th july.Then again on 11th july..there was pain in my abdomen & i bleeded for 4-5 days..Than on 26th july, I again got down.I consulted a gynacologist who did my ultrasound & found a cyst of 1.8 cms in my right ovary..But she told me nothing to worry about & adviced me to take novelon for 21 days..to balance my harmones...we are planning for a baby .I have taken this medicine for 21days from 28th july to 17th august..& was suppose to get my periods as soon i m over with my 21days course of medicine..But have not got my periods till yet..Is there any chance of getting pregnant???I have been vomiting for last 3 days & there is pain in my abdomen & legs..