The running back fumbled one of his eight attempted carries against the Tennessee Titans last Sunday.
The 28-year-old told the team's website: "I couldn't sleep after the game. I wasn't happy with myself, I wasn't happy with how I played. I am trying to put it behind me, but I am such a competitor I couldn't let it go for a couple of days. It kind of stuck with me.
"A bunch of guys told me keep your head up, asked are you okay, we know what you can do. I don't want guys to have to say that to me. If guys are saying that to you it means you are not doing what you are supposed to be doing.
"We just need to work to get better, starting with myself. I need to take care of the ball better. It was an all around bad game for the running game. It's really a whole group effort."
The Steelers face the Cincinnati Bengals this weekend.