How can I fix my car?

You could have possibly seized the engine! Replace oil and see if it turns over

One of two things happened. You ran it out of oil and it seized or it threw a rod and dumped all the oil out.

i never heard a knock for it to throw a rod. if its sized does that mean the motor is done

Yes you would have to get it replaced if it seized. You could have also lost the oilplug from the oil pan underneath the car which is possible if you had recently gotten a oil change and they didn't tighten it enough. Let me know