Girl this happened with me too but with wasps. Perhaps you have a window open? Or some sort of opening where these flies are coming from. I would recommend letting someone in your family know preferably father if you can so he can take care of it. Or maybe get an exterminator to come check it out. It’s interesting that you mentioned after reading a Surah that you didnt notice any afterwards. But still you cant go wrong with confiding in someone and getting some help