I am not going to say you have or do not have signs of cancer. You already have the family history, you already are experiencing problems, so you really need to go to your ob/gyn and explain this to him (or her). You could have something as benign as a cyst - relatively simple to take care of. It could be something else.
I do know some early symptoms of ovarian cancer can be mild, making this disease difficult to detect. Some early symptoms may include:
An unusual feeling of fullness or discomfort in the pelvic region
Unexplainable indigestion, gas, or bloating that is not relieved with over-the-counter antacids, pain during sexual intercourse, abnormal bleeding, and swelling and pain of the abdomen.
Here are some articles that may help you:
Ovarian Cancer - Diagnosis - oncologychannel MedlinePlus: Ovarian Cancer
Hope you find the right answer and are successful in treating what is going on.