Hi!
Without any images to look at, I will have to make some very un-educated guesses about what may be going on. My guess as to what is the most likely scenario is that the sonographer saw a Nabothian cyst on your cervix. These are extremely common, normal fluid filled cysts that many women have and is nothing at all to be concerned about. Another possibility that I think is less likely is that you have free fluid in your cervix although why that would be present, I don't know. If the gestational sac is above the fluid and the fetal heart is normal, there is once again, probably no cause for concern. I suppose there is a remote chance that you have a twin pregnancy with an empty sac that is lying below the baby at the top of your cervix -- not sure why you would have this without any symptoms of bleeding, etc.
If you were my patient, I would definitely want to discuss results with you before you left the country! So keep trying your doctor!
Good luck! and Congrats!
Dr B
Thank you so much:) I can't find anything on the Internet about this so it was good to get some idea what it might be. That was really helpful, thanks!