abdominal ultrasound scared me! help!

hello everyone, yesterday i had my pre-op testing whi*****luded abdominal ultrasound.  everything seemed fine until she got to my liver.  i saw two round black holes or spots on the center of my liver and they didnt look like they belonged there!  tech asked me if i had ever had my liver scanned or ultrasound on it before.  "no".  do you have any back pain?  "no"  she asked me this twice and then proceeded to take measurements on screen of not only my liver but of these two spots.  each looked about the size of nickle.  NOW  i am scarred to death of what this might mean!  any ideas?  my surgery is Monday March 24.  Of course I am worried about the worse possible thing like cancer. Help! Dawn