When I stopped the car there was plenty of oil in it. Could the reason why the car is running so bad be because the head gasket is bad and there is now poor compression causing the Diesel not to be burned properly? There probably was no coolant, as the radiator was cool to the touch…

Thank you all for all of your help thus far!

Sorry I Thought you lost oil.I still would test before pulling the head.

It could be. Also the reason why it didn't want to turn over could have been hydro lock from the coolant in the cylinder.

The next step is to do a leakdown test.

Don't bother compression testing since if you have coolant in the cylinder it could show a normal or higher than normal compression despite a blown gasket.