Firstly, many of these , being told to wait and see (especially after previous losses) is a stressful thing to deal with.

I had this due to a sub-chronic haematoma being adjacent to the sac. Unfortunately it didnt end well for me because the sub-chronic haematoma grew and since I have anticardiolipid syndrome my blood is prone to clotting and this caused the sac to detach greatly. But I did do plenty of research and found that a great many people with this went on to have successful pgs, I just wasnt one of them. You have a really great chance, so try not to worry (easier said than done), it will probably resolve itself and you will be fine.

Wishing you all the best.