7 Week Ultrasound

Hello,

I am looking for some advice or hope. Yesterday I went for an ultrasound at 7 weeks. The doctor had a hard time finding anything in the sac. After searching, I was told two different things. The first thing I was told was that there was no baby that grew in the sac, and then he said there was a baby measuring 6w1d and no heartbeat. Then, the nurse stopped him and said she thought she saw the heartbeat. We all three saw it on the screen. It appears the baby was smashed up against the wall of the sac and wasn't easily visible. He was not able to get a measure of the baby, but said the heart rate was around 140 bpm. He wants me to come back next week for a follow up ultrasound. I have been so miserable and worried since. I had a missed miscarriage last year at about 11 weeks. Has anyone had an experience similar to this and everything turned out ok?