life long diesel mechanic here. These are my thoughts. I can say you probably lost the prime on your pump after jelling or have plugged your filter with wax.
Her is what I do.
First put a white bottle of power service in the tank.
Next Follow the fuel line from the tank to the engine. Does it go through an electric or cam driven pump? If so does it have any type of leaver, piston or bulb that you can pump to prime?
Regardless take the fuel filter off fill it half with diesel and half power service 911. Put it on. Does the filter housing have any leaver, piston or bulb?
Now Follow the line to the injection pump. If you found any type of hand pump you can use it to prime the lines and filter Here is how.
At the injection pump there will either be a pretty obvious bleeder screw or you can crack the line where it meets the injection pump.
If you didnt find a prime pump you continue following the fuel line it will be split into separate lines for each cylinder. Follow those to the head. They will usually meet the block with a flared nut type fitting like this
View attachment 311210
Crack some of the fittings loose and turn the engine over for a few seconds or until the engine tries to fire. Shut it off and immediately tighten the lines so no more fuel leaks out.
The engine should now start. It may be rough while it works the air out of the lines. In the future put a white bottle of power service in the tank and run it through the lines before cold whether hits.