Be aware of the fact that your diesel does not have an electric fuel pump like the gasoline engines do. It is a mechanical fuel injector pump, with individual high-pressure plungers for each cylinder. I doubt that you need a new pump.

With 18°F weather, your fuel may have started gelling. Try an anti-gel additive in future cold weather to prevent this from happening. Also you may need to clean the pick-up screen in the tank. Search for fuel pick-up screen, as this topic has been covered before.

Good luck!