Finding baby heartbeat .!

So I purchased a fetal Doppler and tried it at about 10 weeks 5 days with no luck . I tired again at 11 weeks 2 days and I got a reading on the Doppler of 120-139 it would range in between those numbers . But even with the volume all the way up I could only hear a VeRY faint beating and over top of that I heard LOTS of wind sounds. The screen would blink out and not pick up a number but when it did it would be 120-139 . The highest I've gotten using the Doppler . Should I assume that it was baby .? Or could it be something else causing the ready to fluctuate and not stay on the screen constantly . Also when I would move just a lil the reading would go back low to 80-90 assuming that would be my heartbeat .

First time mom everything is new to me . First appointment not until next Thursday at 12 weeks just needed some reassuring.