First of course, we'll rapidly turn to a conservation economy where energy(and critical commodities) are used only for necessities , probably under some kind of martial law. And of course we have some huge reserves for a case like that.
But , we have such a huge redundancy in food. If we go to the basics, people can live on a big bowl of rice/wheat a day. That comes down 100-200g per person per day. that's tiny.
We also have some amount of fuel diversity - some vehicles models can run on pure ethanol, some can easily converted to natural gas(LNG), and we already have 40K LNG based trucks in the u.s. .
Also there is at least one plant that can make fertilizer from LNG, and others can be built.
As for drugs, which are usually made using precursors from oil derivatives, there are new methods to make those precursors from other means. And some drugs are'nt manufactured locally , but it's possible to import using fuel reserves,or by converting ships to lng.
And since it's under martial law, i assume we will work on rapidly converting our economy to LNG, so as to not be dependent on reserves and increase the living standards .