Doppler

I am 15 weeks 5 days currently with a mmc back in March. I am plus sized so it was hard for me to find the babies heart beat when I did I couldn't help to check frequently. Friday I was just checking in no problems hear the baby just fine today is Sunday and I can't find the baby. Anyone else have this? trying to not be too concerned and I know people have opinions on at home Dopplers. curious if maybe the baby moved and I just can't find it or if anyone else has had experiences like this. Thank you