Has anyone used this app to listen to your baby's heart? The reviews are really good but I wanted to…

Has anyone used this app to listen to your baby's heart? The reviews are really good but I wanted to see if anyone on here has tried it? Also, I wanted to see if anyone else is having bad headaches, some cramps, and have been getting light headed a lot? I've been like this for three to four days now. I know I had fluid in my ears a week or so ago and have been taking amoxicillin for it but it's making me nervous. I'm waiting on my ob to call me back and let me know if I need to come in or not. But I've also been getting very tired at the drop of a dime. I'll be fine one minute and the next I feel terrible.