When I went to have my OB appt at 16 weeks, to book in to the hosital (only time I saw an OB) she couldnt find the HB with the doppler, so had to go get the portable u/s machine to find it (mind you she said nothing the whole time - Im glad this is not my first baby so I guessed what was going on)

If you are going to be that stressed, go have mopnitoring done at the hospital - it will be better than you stressing over what is very likely not a problem