Fluid in uterus prior to scheduled FET

Hi girls last Thursday I had an ultrasound and blood work, estrogen came back great and I was told to begin my pio injections on 2/14 as scheduled. Unfortunately there was a small amount of fluid in my uterus so I go back tomorrow morning to have another ultrasound to see if it's gone, if it's not gone they will cancel my FET that's scheduled for Wednesday. I'm hoping someone has some insight or advice on anything I could do to try and get rid of the fluid, my nurse said Sudafed sometimes helps. Help!!