The Saracens fly-half played in four of the Red Rose's five matches, including the final-day defeat to Wales that cost Stuart Lancaster's men the title and Grand Slam.
Farrell, 21, admits that defeat in Cardiff - in which he kicked England's only points with a solitary penalty - left him disappointed, but he is convinced he is a better player than when he made his RBS 6 Nations debut in 2012.
"I was gutted after the game and I was drained from it too," he told the Daily Mail.
"You just get away from it and start thinking about the next weekend and the next game, then every now and again it just kind go catches you and you feel gutted again. But I'm fine now.
"I've come a long way. It's like chalk and cheese compared to last year, but there's a lot I can improve on.
"I think my depth is better - I'm coming to the ball better and seeing chances. I think I'm better with my execution as well. Hopefully I'll keep getting better for the next ten years."