Take the line loose from the out port of your fuel pump and if you get no gas coming from the pump, then the pump is either fried, or the filter in your tank is stopped up with rust. My first suggestion is to take the sending unit out of the tank after you have drained the tank, and see what kind of condition that filter (sock) is at the tube on the sending unit. If it is clean, then your pump has gone south. They are cheap and easy to replace. By taking out the sending unit on the bottom of the tank, you will be able to get a visual idea of just how much rust is in the tank. If there is a bunch, then replace the tank. Since you posted in the classic section, I will assume that you have a classic Mustang.
On edit: If you are getting a good stream of gas from the pump, then you have a stopped up fuel line between the pump and the filter.