England defender Tyrone Mings said his “sanity had collapsed” in preparation for Euro 2020 because he felt people doubted his place in the squad.
Aston Villa center-back started England’s first two group matches as Harry Maguire recovers from injury.
Mings, 28, spoke to a psychologist to help him cope with the pressure.
“When 90 to 95% of your country has doubts about you, it is very difficult to prevent it from encroaching on your own thoughts,” he said.
In an interview with the Sun, Mings added: “I had a tough time going into the opener against Croatia.
“I think I’m much more hardened to outside influences now, but my sanity has collapsed.
“And I have no shame in admitting it because there were so many unknowns about me going to this game.
“I was probably the only name on the roster that people thought, ‘not sure.’ And that was something I had to overcome.
“So I worked a lot on this with my psychologist. I’ve been given a lot of coping mechanisms – be it breathing, meditation, or just learning to put myself in the present moment. Stop letting your subconscious take over.
” It was hard. I didn’t sleep very well before this first game. “
Mings helped England keep their clean sheet as the Three Lions started their Euro campaign with a 1-0 win at Wembley. Six days later he helped them get another shutout as they drew 0-0 with Scotland.
He was voted England’s second best player in both matches by BBC Sport website readers.
Maguire returned to the squad for the final group game against the Czech Republic, with Mings as a late substitute in the 1-0 victory.
The former Bournemouth player took part in a BBC documentary alongside Prince William last year on the importance of taking care of your mental health.
Mings revealed that he spoke regularly with a psychologist between games, having initially sought support as he recovered from a serious knee injury.