Ovarian cyst , please help.

Hey ladies , so when I went for my first ultrasound at 11 weeks , I was told they had found a cyst on my ovary about 3cm big... Said not to worry about it but I just went for my 20 week ultrasound & said the baby was fine but the cyst was still there & measuring 5cm which is an inch & a half big... Now all day today I've had pretty bad pain on my lower right side of the front of me & lower right side pain on my back... Could that be the cyst rupturing !? What should I do ? I'm waiting to hear back from my doctor.