Need help bad and u guys I come to first

[Firstdiesel6.0]

A few days ago I noticed what looked like diesel spray on the back of my excursion, it was light but stupid menu disnt worry about it. Yesterday I looked and saw more and found it was leaking from the back side of the motor above the bellhousing frm what I could see. Turned out it was leaking worse that what I thought. I got on here and read andew things to look for. I checked my oil level to make sure it wasn't leaking into the oil and it was fine and didn't smel like fuel or anything. While driving it would buck a bit around 35 moh but add mor peddle and it stopped and was fine. Started fine etc and pretty much ran normal. Has been super cold here last few days (0-15 degrees) so I plugged her in the last two days. This morning my wife let it warm up (actually not) for about 5 min (I have her scared about idling to long), she drove off and it started running rough shebeens and stalled. Then it wouldn't Start at all. Had it towed home. I just got home and tried to start it and it only cranks but won't turn over. I put a bottle of additive to keep the Durkheim gelling etc 3 days ago. The check engine light is not on. The leak looks like it's leaking good. The sight said possibly an injector bad leaking fuel but nothing in the oil, another post said there is a fuel line (return fuel line?) in that area that the rubber gaskets go bad on at the fitting and that could be it. Sounds like that's the most obvious cause due to the location and amount of fuel.
My oldest baby girl is having her baby any day and now Christmas so money is tight. I did buy an extended warranty when we bought the excursion several months ago. My questions are 1- what could be causing the fuel leak, any idea exactly where it might be coming from (anyone had the same thing happen) 3- would this cause it not to start 4- isn't something I could fix 5- my warranty is only a drive train warranty. My baby is an 03 excursion with the 6.0 and has 156k on her. I love the 6.0 and know it has
Potential n I wana keep it. Please any help and ideas guys. Thank u in advance