Got a fetal doppler, now I'm paranoid

I initially got it to ease my fears since I had a previous miscarriage and it's been working great! I felt so happy to hear the heartbeat and know my baby is ok in there

but recently I've been seeing/hearing things like they aren't safe and could be dangerous now I'm back to freaking out again!

I need some words of advice to calm my nerves. I think I'm sending it back in the morning 😔

Edit: I do use in moderation, approximately 10 minutes a week. And there is no doubt we've found the heart beat, that is not my concern. Thank you.