My best friend was diagnosed with stage 4 ovarian cancer in June. The first test that indicated cancer was the CA125. Have you had that test? If not, please ask your doctor why not. It could give you peace of mind before the surgery. Her tumors were so huge that a hysterectomy couldn't be performed, so she started chemotherapy. She's doing great, by the way.
Good luck. Just take it easy after the surgery. And as far as not having paid time off, remember that you'll be spending less money by not working, (gas, car maintenance, lunch, etc).