Cramping In Abdomen, Brown Discharge. Is It A Cyst In Ovary?

Hello, I am a 14 yer old female.. I have been experiencing some pain cramping and a pressure feeling around my belly button and abdomen , along with swelled sac like structures on each side a tiny bit below my belly button, I was due to get my period on the 34th of this month and I got what I thought was my period that night but it was unusual...it was a dark brown discharge and only lasted about 3 days my periods usually last 5-7 days and are a good amount of blood..I m wondering if this could be a cyst on my ovary or possibly a hernia , any help and information is greatly appreciated!