The surging cost of filling up her car is taking a toll on Melissa Miles's finances — and her classroom attendance.

A full-time student in social work at Eastern Michigan University, she commutes daily in her 2015 Chevrolet Sonic between school and her home 80 miles away in Hillsdale, Michigan. But with gasoline prices in the state now averaging $4.80 a gallon, the 42-year-old told CBS News she has started skipping some classes to avoid the drive.

"Literally every day, I have to figure out, do I have the groceries for the week, or do I have the necessities for today? And then compare it to, can I miss this class?" said Miles, a single mom whose budget includes looking after her five-year-old son.

Miles is one of the millions of U.S. motorists grappling with sharply higher prices at the pump due to the Iran war. The national gas price rose on Wednesday to $4.54 a gallon, up more than $1.50 since the conflict erupted in late February, according to AAA. 

The cost of diesel has also jumped to $5.67, up from $3.54 a year ago, and is threatening to drive up the prices of countless goods delivered by truck and rail. 

Although President Trump said this week that the U.S. is making "great progress" in its negotiations with Iran, economists and energy experts predict that fuel costs are likely to remain elevated for months to come. 

Mark Zandi, chief economist at financial research firm Moody's Analytics, expects gas prices to settle at around $3.50 a gallon by the end of 2026, roughly 50 cents higher than the cost just before the war.

White House spokeswoman Taylor Rogers told CBS News that Mr. Trump remains committed to lowering fuel costs for Americans.

"As the president continues to exert maximum leverage over Iran with the ongoing successful blockade to bring this conflict to an end, we will see global energy markets stabilize and gas prices plummet back to the multi-year lows Americans enjoyed prior to the start of Operation Epic Fury," Rogers said in an email.

Sacramento, California, resident Daniel Hock expressed frustration with the state's skyrocketing gas prices, which at $6.16 a gallon are the highest in the country.

"I ultimately am the one footing the bill under a presidency that said that my gas prices would go down," he told CBS News.

The 33-year-old, who works as a university admissions adviser, said he now spends roughly $100 a week on gas, or roughly 9% of his pre-tax income. That's money he'd rather use to pay down the debt he accumulated during a recent four-month period of unemployment, he told CBS News. 

Not surprisingly, low-income Americans are taking the biggest hit from higher fuel costs, given that they spend a larger share of their income on gas than those higher up the income ladder. Bank of America data shows that in March, low-income families spent 4.2% of their income on gas, compared to 2.7% for wealthier households.

Steph Thornton, a 42-year-old single mom of two, said higher fuel prices are hurting people like her who live just above the poverty line. The Macomb, Michigan, resident, a community health worker, uses her 2017 Ford Escape to conduct home visits with clients. Thornton estimates she now spends about $400 a month on gas, compared to $320 earlier this year when prices hovered around $3 a gallon. 

"Many of us haven't even regrouped from the pandemic," Thornton said. "Things are just hitting us back-to-back."