Hello ChristieB1,
I can totally relate to your worries, but it is okay and normal to be worried about this, as even the word 'cancer' brings fears to our lives. Your OB/GYN is correct, and so is Missy3037, that if it were ovarian cancer, ultrasound would have showed more than it did.
However, you can never be too safe, and I suggest you to take CA125 blood test. This test is not an absolute indicator for detecting the presence of ovarian cancer, but it is well known and used by clinics all around the world.
Also, if able, request a CT scan of your pelvic area. It would show a lot more than ultrasound, and gives doctors a broad view inside.
By the way it sounds, the 'fibroid' may be causing all the symptoms indicated. Severe 'bloating' and 'lower back pain' would be due to the presence of tumor inside, also a build up of gas. Whether it be cancerous or benign, no one knows yet.
Your children must be adorable! and proud to have a mother like you!
We are all here for you, and again, worrying is normal, so stay positive and get involved in more family activities to spend lots of quality time together!
If your ovaries were normal in the US then you don't have ovarian Cancer. Did you get a teansvaginal US? You can ask for that and for a CA 125 blood test. Sounds like possible endimetriosis. I had OC and I know people who have had fibroids and endimetriosis. Sounds like you have what my friends had. I had OC and your ovaries have a huge mass on them. You can get the transvaginal US to be sure. Sometimes when OC is very small, caught early it is hard to see on a regular US. I wouldn't worry though sounds to me like you do not have OC.