When did you first see the heartbeat on US?

I went in on Tuesday for my first ultrasound. We aren't sure exactly when I ovulated because my cycles have been so irregular. My best estimate would be I ovulated sometime the week of July 23. That made me about 5 to 6 weeks. The gestational sac also measured 5 to 6 weeks. We didn't see the fetal pole. I go back in 2 weeks for another ultrasound and the wait is killing me! I've had 2 early MC so I just want to see my baby and it's heartbeat to be reassured it's "viable". Did anyone have a similar experience? TIA