Stones, a regular starter in Gareth Southgate's lineup, came off the pitch at half-time in last Friday's loss to Iceland after appearing to roll his ankle before spending 36 hours isolated due to illness midweek.
The defender has said he did not suffer any serious injuries and has returned to training to be available for England's opening Group C match.
"It was almost like my big toe in the line straight down my foot and you think 'I have fractured it'," Stones told British media on Friday.
"You think the worst at the start and we got some scans back and it was really minor stuff, which is great. Then I haven't been that ill in…I couldn't tell you how long. It was a real rough 36 hours.
"It could have been a lot worse than what it was and I was glad to get through training on Thursday. Now I feel great physically. I am looking forward to it now."
Stones, capped 72 times by England, said he believes the country can improve on their 2021 Euro performance when they lost in the final to Italy.
"I'm a big believer in not hoping we can win but believing we can win," he said. "It's a simple message. I think all of us in the room hope we can win but believing is a totally different thing. That's a powerful thing."
Following Serbia, England face Denmark on Thursday and Slovenia five days later.