12 week check-in worries

Hey all. Had my 12 week check-in with my doc on Tuesday morning and we could not find baby using the fetal doppler. We tried moving, different positions, up down and all around - nothing. This is my 4th pregnancy (1 🌈, 2 F) and with my last pregnancy I experienced an anterior placenta. Doc said that could absolutely be the case again, or because this is my 4th pregnancy baby could be high/low and tucked away.

I’m worried/not worried. Doc isn’t worried, and I’m going back in a few weeks for another check-in. She said given I still feel pregnant and have symptoms, and at the first ultrasound we heard the heartbeat, things are probably all good. Has anyone else experienced this before? Would love to put my mind at ease or know if I should be a little more worried.