Victory over Leeds in Sunday's semifinal came in the week of former manager Liam Rosenior's dismissal.
Lavia told Chelsea's website: "Sometimes when you have a few results that don't go your way, you feel like everything is against you. The reality is that as long as we stick together, it will turn around in the end, especially given the quality of the team.
"It was good for the team, and you can see that we worked hard to get it right after Tuesday, which, as a team, we thought was unacceptable; it was important to get it right at Wembley. We used that frustration heading into the next game to try to get it right, and we did that against Leeds."
The Belgium international also said of caretaker manager Calum McFarlane: "We know Calum very, very well.
"It’s just about adapting to what has happened and trying not to look at the past and moving forward as soon as possible, especially in this competition where the aim is to get a trophy, which we know is possible. We tried to prepare the game as best we could."