Ovarian cyst. What to do now?

I was diagnosed with a cyst on my left ovary (11cm x 7cm) in February when I woke up a morning with severe pain on the left side of my abdomen. I had missed my last period & had fallen sick that week without any reason. So it was quite surprising. A doctor drained out a bit of fluid through syringing to ease my pain that day & referred me to another doctor. After my pain was eased, I felt completely normal & healthy, even though the cyst was there. But it had shrunk a bit due to the drainage. My doctor prescribed absolutely no medications & asked me to follow a healthy routine & wait for it to go away on its own, which it even did. After 15 days, I got my period which was quite heavy. Got an ultrasound after that & the cyst was gone! Thereafter my periods were all regular & normal. But I missed my last period and fell sick randomly again. Got an ultrasound this week & discovered a cyst of 5cm x 5cm on my left ovary again. My doctor has again prescribed no medication. What to do now?