during reproduction life, cysts will come and disapear due to hormones. i think in this situation, you should not worry. But cancer in the family may caution you to be careful but not to worry. Your Gynacologist may repeat Ultra sound
and she will do some other tests, if suspicious about ovarian cysts such as tumour marks and ct scan
etc. At present you should not worry, but don't forget or neglect the appointment by your Gynacologist.