What Causes Delayed Periods On Withdrawal From Yasmin Pill?

I have recently come off the yasmin pill (end of november) and have not had a period since. I have taken several pregnancy tests which are negative. Had some blood work done at the doctors and everything came back as normal. We are trying to conceive. Today been experiencing a slight throbbing and burning sensation in left ovary area. I am worried it may be a cyst or something. I am from the uk. I have booked back in with my doctor at the end of the month. But am just abit worried about this symptom that i am experiencing. Thanks.