Hey LtlPanda...my DH and I were also a bit concerned about it. I did a HPT last night and it was BFN. We are going back for another US next Monday night to check everything again. I presume if this sac like thing is still there then some more tests will be done.
Good Luck with your IVF
Hey Penny....I would just keep BDing until AF shows or doesn't show. And still keep temping cause you might just be Oing late. Have you noticed any change in your cervical mucus?
Have a great day ladies
SAM