Fetal size smaller

Hi everyone, wanted to see if anyone experience this before. I went for a ultrasound scan at 5th week. There was only yolk sac I was having brown discharge went to a&e, everything was okay,baby was growing at 6th week. But at 7th week baby didn't have heart beat during ultrasound and size became smaller. Doctor say to prepare mentally as it maybe possible miscarriage. There will be another scan to check one week later. Have anyone experience this before?#pleasehelp #firsttimemom #advicepls #firstbaby