Didn't sound like a heartbeat...

I went to the doctor today for pelvic pressure/pain. My midwife states everything feels and looks normal and sometimes with your 2nd baby, you feel things quicker than with the first. She checked my cervix, which was still closed,.thank God. Then she checked babies heartbeat. I was listening for the fast paced beat like normal. What she claimed was my babies heartbeat sounded like a bunch of static and she kept moving the doppler like she was trying to find the heartbeat. The sound never changed. So now I'm freaking out. Did she really hear my baby or not? I'm tempted to book a private ultrasound to ease my mind.