Home Doppler

My doppler arrived! It's not as easy as I thought, I keep picking up my own heartbeat. I've already had to appointments and have heard the heartbeat nice and strong. But this thing is tricky, I'm 11 weeks anyone else had this issue? The only thing I can think is I'm on the tad on the heavier side so maybe there's too much cushion down there for it to read through lol?!