phone overheating and powering off

So my iPhone 5S has only done something like this once before. I was using it a lot and it heated up and got real slow so i just put it down for bit to cool off and then its been working fine.

Today i noticed it getting slow again and having it get hot so i put it down to cool off. Now the screen is off and it won't turn on. I don't think its out of battery and i believe i just need it to cool down for a couple hours but its never done it before to where it turns off and such.

Its a little hot right now so I'm not sure what to do. Theres no history of water damage or anything so i have no idea what could be wrong with it.

Thanks!