This concerns me indefinitely

While editing a photo on my 6 P. in IG a random audio began playing on my phone. My instant reaction was just to turn it down because its 7am around the time it happened and didn't want to wake anyone. The audio didn't turn down no matter how many times I hit the decrease volume button. To me i thought maybe it was a bug in instagram and I was listening to someones video but as it continued someone started talking. The voices were recognizable and between two people was a conversation that had yesterday... I realized it was my own voice and my manager talking to eachother, which couldn't be a possible recording as I am never on my phone at work. It sorta struck me the wrong way so I searched every app on my phone that could record but found nothing. Not sure whether or not I've been hacked and someones screwing with me or this is a bigger problem??

If anyone has a story or problem like this please explain.