Go to gyn and ask for an ultrasound to rule out a pelvic mass. Most are fibroids not cancer. I just had a giant fibroid removed through an abdominal hysterectomy and it felt as you describe (although I just thought it was menopause weight gain and my gyn found it at an annual exam). Just so you know, the process was- ultrasound. When ultrasound confirmed a mass, I was instructed to get a MRI, a bloodtest for ovarian cancer marker, and an appointment with a gynecological oncologist (the practice at Sibley was where I was referred). All of this was scary but not cancer in my case.