Don't stress!! I'm 13 weeks and it took me forever to find mine today..it was super low and the heartbeat was faint at first...I watched a video and it helped a ton!!!
What kind of Doppler? I found baby at 9 weeks with mine. Go low towards pubic area, press downwards kinda hard/firm and move in small circles. But don't get upset if you can't find it yet. Just try again another day or week. No stress.
It says you're 10 weeks right? You're still really early. I don't think most home use dopplers will work until at least the beginning of the second trimester.