Cahill looked set to partner John Terry in the centre of defence for the tournament in Poland and Ukraine, but suffered a broken jaw in the warm-up friendly against Belgium.
Joleon Lescott stepped in and received praise for his performances as England reached the quarter-final stage, and when Terry was ruled out of the World Cup 2014 qualifier against Ukraine, it was Phil Jagielka who partnered the Manchester City defender.
|ENGLAND PLAYERS BACK GERRARD
|The captain has received the support of his team-mate following his red card against Ukraine
"I feel like I'm back to square one with my country," Cahill told The Sun. "Before these last two England games, I probably didn't realise just how much damage that injury did to my chances.
"Towards the back end of last season, I'd forced my way into the team and was starting most matches.
"In the weeks before the Euros, I felt as though I could be a big part of that competition. But to have that unfortunate injury has clearly set me back in the pecking order.
"I wouldn't say I was surprised when I didn't play against Ukraine. I was more disappointed and frustrated. It feels like things are out of my hands again.
"You think you're progressing, then all of a sudden you're back to square one. That's the way I feel at the minute."
Cahill revealed his disappointment at having fallen down the pecking order so quickly but insisted that he remained determined to earn a place in coach Roy Hodgson's starting line-up.
"Going into the Euros, I was hoping it would be me and JT as first-choice centre-backs," he continued. "But these knockbacks keep happening to me.
"Before the Belgium game, I'd pushed myself into a position I was happy with and my form was good. But Joleon played well at the Euros and I have no argument with that.
"You wait for your chance to come along and you take it. My goal has always been to be a regular fixture playing for my country and I thought I was getting close to achieving that.
"Now I feel as though I have to start again and get myself back up the pecking order. I've done it before and, hopefully, I can do it again.
"It's just a matter of fighting back to where I want to be. The only way I can do that is by getting my head down, working hard for my club and going again."
Cahill bore no grudges towards Hodgson for his non-selection, however, and added that he appreciated how the national team boss was happy to explain his choices.
"The boss always gives you a little idea of the reasons behind his decisions," he said. "He lets you know his thinking.
"He's very approachable and easy to talk to. You never feel uncomfortable with him and I spoke to him a lot when I was out injured."