No heartbeat found with Doppler at 10w

Last week we hoped to hear the heartbeat at 10w1d but my midwife could not find it with the Doppler. She was not worried & told me not to. She said she didn't expect to find it but thought she would try, that it was still too early & everything looked to be progressing right along. I don't go again till October 13th which will be almost 4 weeks & im worried sick after having a ectopic earlier this year. Had 2 early ultrasounds & saw heartbeat at 6w. Read a lot about missed miscarriages. Anyone else not hear it at this stage but everything turned out ok?