5.5wks, gestational sac and yolk have not grown

B.

I thought my period came 3 days early but on the second day I tested positive for pregnancy (4.2wks). I went straight to the doctor worried I was miscarrying (I miscarried in March). She sent me to the hospital for scans. The scan showed a gestational sac and yolk. I was told to come back 10 days later. Over the 10 days I continued to take pregnancy tests and the lines got darker so I was feeling really positive. When I went for my second scan today (5.5wks), the midwife said the sac had not grown. She thinks it is a miscarriage but will scan again in a week. Has anyone else experienced this? Is there any chance the baby could still grow?