As the resumption of President Donald Trump's illegal war with Iran sends gas prices back to an average of $4 per gallon, a poll released by CNBC on Friday shows Americans' perceptions of the US economy growing increasingly negative.The latest CNBC All-America Economic Survey finds that 61% of Americans are feeling pessimistic about the current state of the economy, with just 25% saying they feel optimistic.This marks the most pessimistic Americans have felt about the economy since December 2023, after the US suffered through an inflationary shock primarily driven by the re-opening of the global economy after the Covid-19 pandemic.Americans' biggest concerns are with the cost of living, with voters expressing particular worry about gas and grocery prices.Forty-seven percent of Americans surveyed say they have been cutting back on food and medical care to save money, while two-thirds report reducing spending on "non-essential" purchases, such as restaurant meals and entertainment.The survey also finds that US voters are pinning the blame for the state of the economy squarely on Trump, as just 38% of Americans approve of his economic performance while 60% disapprove. Americans are even harsher in their assessment of Trump's handling of the Iran war, with just 35% approving and 63% disapproving.Democratic pollster Jay Campbell, a partner at Hart Research, told CNBC that the recent drop in gas prices from their peak earlier this year is not enough to put Americans in a better mood, especially given that prices are headed up again."People are still paying a lot more for stuff than they were a year and a half ago, two years ago, and that’s recent enough in memory that it still hurts and it still drives a lot of anger," said Campbell. “When gas prices drop 50 cents for a month, that’s just not enough to make up the difference."According to data published by AAA on Friday, the average price of gas in the US is now $3.98 per gallon, 10 cents higher than it was a week before. The price of diesel fuel has also risen back over $5 per gallon, up 15 cents from one week ago, according to AAA.Despite Trump's brutal polling numbers, the CNBC survey finds that Democrats currently have a modest four-point advantage in the generic congressional ballot, which Campbell said "doesn’t point to a wave [election] at the moment."