Fluid on ultrasound.. two weeks before FET

Has anyone had this happen??? I started Estrace last monday.. i had stopped the pill a few days prior to starting it and last wednesday had some light spotting from stopping the pill. well yesterday my ultrasound showed fluid by the cervix.  the nurse had no idea and the u/s tech seemed concerned.. they said the RE would look and message me.. Well all i got was to continue estrace and be back next week for more blood and ultrasound..  I'm really nervous now.. could it of been the blood still there? I am going to message my Re but i won't hear till tomorrow. wondering if anyones heard of this..  and then today i was stupid and went and did weight machines cause i felt so stressed. it only made me more stressed.