idk where i could put this ...

I'm literally going insane! my daughter said look mommy a bug I look down and its a freaking maggot!!! WTF?! idk where it came from we take trash out daily unless I throw food in it then it goes right out dishes stay out of the sink and clean I sweep floors daily I vacuum weekly no food is ever left out or anywhere so im so confused. I have seen two flies come in when the door was left open that was a few days ago and as soon as I could find them I killed them and I have started seeing more of them and idk what's going on! is there something I'm missing? we keep things clean what's causing them?????