Even Russia is surviving under the heaviest sanctions ever because China is helping them. Remember we are also friends with China who is the most powerful country in the world at the moment.
If the US sanctioned Pakistan then I expect China will help and I'm pretty sure Russia will have no problems supplying all the oil and gas we need. Pakistan can expand into Russian and Chinese markets without having to trade much with the US at all. What do we actually need from them which we can't get from China and Russia??
The majority of 'trade' that Pakistan does with the West is actually food products consumed by overseas Pakistanis, not White Westerners.