The 29-year-old, ranked fourth in England, has been out since January and will miss the rest of the season.
"It feels pretty rubbish," the Guernsey player told BBC Sport.
"I have saved and planned for an injury break, but it's still never easy and, to be honest, I never expected I would be injured for a nine-month period."
Simpson continued: "Squash is a sport where pretty much all of my wages are made up from tournament earnings and appearance fees for teams and exhibition matches, so essentially I'm unemployed for nine months this year."
He had intended to play on despite the hip problem until April, but suffered an abductor muscle injury at a tournament in New York, which brought the operation forward.
Ranking protection in squash means he will return at number 35 - 10 places lower than his ranking at the time he suffered the injury - but Simpson expects it to drop "quite significantly" unless his results are good when he makes his comeback.
"It's very difficult actually when you compare it to a team sport or many of the other Olympic sports, where the athletes have really good funding which covers most of their wages," he said.
"There is going to be a big mountain to climb, but at the same time I know that I deserved to be where I was in the rankings.
"If I can get my level back then I'm confident I can climb the rankings reasonably quickly and start competing for titles again."
World number 28 Chris Simpson says he is "essentially unemployed" as he recovers from hip surgery, which will keep him out until September.