Couldn't hear heartbeat on doppler

Shayla
I had a prenatal appointment today I'm 11w5d the physician tried to listen to the heartbeat but she couldn't find it, although she heard the placenta which she said was good. I saw the heartbeat at my 8w2d ultrasound and it was strong at 167bpm. She said I shouldn't be worried because they often can't hear it before 12 weeks but I can't help but be! Has this happened to anyone else? Have an ultrasound in a week I'm trying to be patient but I'm so anxious 😭