Heart beat

So I guess I'm a little confused as well as upset. I have been reading a lot of post with people saying they got to hear their babie's heart beat. I am now 10 weeks along and still have not heard the heart beat. I have had 3 doctors appointments. At each appointment the doctor has done a vaginal ultrasound and I have seem my baby as well as the flutter of the heart but I have not heard it. I asked my doctor about hearing the heartbeat and he keeps saying it's too early and I have to wait until about 12 weeks. I feel like he's lieing to me. Tomorrow I have my 10 week check up and a few tests, I'm going to ask again. Am I the only one who has not heard the heart beat by now?! I feel fortunate I have had so many Sonagrams because I know a lot of people have to wait for that but I feel like when I actually hear that little heart it will be a real moment that I'm so excited for!