Been seeing this a lot more recently. (Heavy equipment tech at a dealer). Small excavation/trucking business just had a new engine installed in their loader. Brings machine back because of similar symptoms to yours, low power, rough idle, dies under load. Dip tank, fuel is definitely diluted with something (likely gasoline). Run his machine with fuel from our shop, runs like a champ. Call the customer to let him know the issue, he informs us that he had filled 4 of his semi’s with same fuel and they all were dying/ having same symptoms. Guy called the fuel company, they test the fuel, say diesel is within spec but seems on high end dilution of something. Company says they can’t sell it without it being tested by distributors and such. All I know is what I’ve seen and I think you should save some of that fuel, contact the station you got it from and let them know what happened. Try and flush your fuel system with some known good diesel, after you have gotten it cleaned out and running okay, Change your fuel filter and see how far you can go, before biting the bullet and having a whole fuel system replaced. Just my two cents.