16 week pregnant and a little worried about the baby moving?

I havent been able to feel my baby yet nothing at all is that weird? i am so anxious to feel somthing!!! I also went to the doc 4 weeks ago and she couldnt hear the heart beat on the doppler so they sentme in for u/s and everything was ok! I rented a dopppler and i cant ever find the heart beat either! i may not be doing it right.. i go back to the doc. tuesday so hopefully everything is ok? any advice