it should pick up on you I found mine at 12 weeks. and it's kinda hard at first just lay really flat and still and get it really about the same place you pelvic bone is and just move it around
the placenta sounds like a swooshing noise on mine and the heart beat is something that can definitely be told apart from that! Just have patience. It might still be to early for you to find yours. they work different on everyone
I got mine today also! I'm still trying to figure out the placenta pulse from the heartbeat, apparently it sounds different. I thought I got the HB right away but I watched a YouTube video and I guess I was wrong.