Low Heartbeat

Went for 2nd ultrasound, should be 7 weeks, baby had grew from the first ultrasound and there was a heartbeat this time but it was only 89, they basically told me there was very little hope and to come back in a week for an us. I go Tuesday, i have no symptoms of a MC, if I had not had the us I would not be worried about anything. I had a stillborn daughter last year, so I am beyond freaked out. Any comments appreciated, good or bad.