The midfielder saw Liverpool lose out on the Premier League title before England were knocked out of the World Cup in the group stage
The 2-0 defeat at home in April, followed by a three-goal lead slipping at Crystal Palace, saw Brendan Rodgers's men finish second to Manchester City in the league after leading with three games to go.
Gerrard's fateful slip, which led to Demba Ba's opener at Anfield, was replayed as the moment Liverpool had let what could have been their first league title in 24 years slip.
"I've probably been through the worst three months of my life," Gerrard told reporters.
"There's nothing else to say is there? If you ask how it's affected me – it hasn't. I have football to play in the future so you have to look forward, not back.
"The only time I think about it [is when I'm asked about it by the media]. I appreciate how big it is when you go out of a World Cup, when you fall short, after going so close in the Premier League title race.
"We have to try to win the league, progress in the Champions League. When you're captain of the team and the group, you can't afford to be down and feel sorry for yourself or mope around."
According to Gerrard, what made the incident hurt most was that it was simply a piece of bad luck and his positive impacts far outweighs the mistake against Jose Mourinho's side.
"That's why it was cruel. I haven't made a mistake, I haven't lost my man at a set piece. I haven't missed a penalty. I haven't made a bad pass," he said.
"Every single person on the planet slips at some point in their life, whether it's on the stairs, on the floor or whatever. For me, it happened on the pitch at a really bad moment.
"But over the course of 38 games, a lot happens for you and against you and that determines if you win the league or not. But that moment happened at a really crucial time and I have to face that. And I will."