please give me advice..

So I went for an ultrasound at 10 weeks heart rate was 164 and baby looked good.. today I went for a check up with my regular doctor.. He grabbed his as he claimed old Doppler to check for the heart and he couldn't find it.. He claims that it's likely just the Doppler and just told me to come back in 4 weeks.. I did argue and I cried and he told me he will see me Jan 4. and try with a new Doppler.. could it actually just be his Doppler ? Should I be getting a second opinion ... this is my rainbow baby (baby after a loss) . I haven't bled at all and zero cramping.. has this happened to anyone.. please 😭