The 32 year old, told BBC Sussex: "It's been difficult not playing and you kind of fall out of love with the game.
"It's been a breath of fresh air to come here. Friends and family have noticed the difference in me and how much I'm enjoying football again."
The former England international had found first-team opportunities limited over the last two seasons, making just eight appearances for the Premier League Champions since August 2010.
"It wasn't a hard decision to come here and in the time I've had so far, it was the right decision," he added.
"The manager [Gus Poyet] has been good to me and I've settled in quite quickly.
"I want to be at a team where I can help them. Hopefully I can be here quite a while."