Waiting for diagnostic ovarian

Hi I am just trying to get myself together. I had a ct scan done 2 weeks ago due to left side lower back pain. Had the ultrasound yesterday waiting for dr to see results but I have a 9 cm tumor on left ovary. I am 58 with 2 adult children. Have FAP hereditary condition. Had my colon removed due to high risk of cancer. The ultrasound shows that the mass has septation and internal echoes which means nothing to me. Had my regular annual apt in July nothing detected. Sitting waiting for drs to tell me what is next. Complex cystic lesion is the description they wrote on the report. Scared