Why does my car act like it's out of gas but backfire when I let off the starter

What is your question?

I drove my car home and shut it off. I went to start it in the morning and it acted like it was out of gas I put gas in it and it still don't start. I go to turn the key and the starter engages. It tries to start and spudders like it's gonna but I let off the starter button and it back fires. What's going on??