The 32-year-old defender made his first Prem start in more than seven months in last week's 3-2 home defeat by QPR and is set to continue against Blackburn tomorrow.
But he admitted: "I won't lie, it has been one of the worst times of my career, to be sitting out while the other lads have been enjoying a lot of success.
"At the time I was distraught. To miss two of the biggest games in the club's history is heartbreaking.
"It did cross my mind about my career. So it's fantastic to be up and running again."