Can't find baby's heartbeat at 6w 1 day?

from my LPN i am 9w 4 days along. From the u/s i am 6w 1day along. the doctor could not find a baby's heart beat, i also found out i have a cyst on my right ovary. he said this is a possible miscarriage. I was told to come back in a week for an other u/s. i'm not having bleeding or cramps, not felling sick. a week seams so long away. could this be true, what the doctor is saying?