Liverpool captain Steven Gerrard admits he feared his recent groin injury could have ended his career.
Gerrard made his first start in six months following surgery on the groin injury in last weekend's 1-1 draw with Manchester United.
The England international, who marked his return to action with a goal, admits the last six months have been the hardest of his career and that at times he feared he might never get back to playing.
"It's only natural that you have doubts," Gerrard told the club's official magazine. "Different things cross your mind from time to time.
"When I got the injury I knew it was going to be a serious one, something that I wasn't used to. I'll admit that I was down, as low as I've ever been as a footballer.
"Before the operation I'd been getting niggles and having injections to play. I knew I wasn't right. I was trying to put my body on the line. But it wasn't the real me and I wasn't the player I want to be.
"I was missing training sessions and coming in the day before a game trying to get that last session in, or having injections to play the next day.
"You can only do that for a certain amount of time before your body gives in, and my groin packed in on me.
"When it happened I was down and it took time before I got back in to a positive frame of mind. It probably wasn't until a couple of weeks after the operation, when I got off the crutches, that I started being really positive again.
"Without a doubt the last six months have been the hardest of my career."