In the last few years, the 32-year-old has suffered with injuries and absences, which has been a concern to Berchiche.
Athletic sit in sixth place in La Liga and are targeting a place in European competition next season.
"It's been a long time since I enjoyed playing football," Berchiche admitted in a club press conference.
"I hope to gain confidence in myself. The team is showing now that it is on the right path. I want to enjoy it again and find my good feelings again.
"I have the confidence of the coach and my teammates. We are in a very exciting season if things continue like this," Berchiche said.
The defender has missed significant game time having been injured for a while with a foot issue, but is expected to travel with the Athletic team to face Girona on Friday.
When asked about his foot problem, Berchiche said: "I did not expect this, this season. Already last season it was a total of nine months [injured].
"I had a terrible time. It seemed like it was back to normal again and again… You have a really bad time, and with the support of the family it's a little easier.
"Now I hope to enjoy myself and that there are no more injuries.
"There are moments that have been more difficult than ever. It was very difficult for me to come to Lezama and play in San Mamés. It has not been easy. Luckily, I have been able to return, but I do not enjoy playing football as I used to.
"These are moments that happen in the life, that have to happen. Now I hope not to injure myself again, try to stay fit as long as possible and enjoy football again, which is what I like the more than anything," he added.
The defender has previously played for Real Unión, Real Sociedad, Eibar and Paris Saint-Germain, who he left in 2018 to join Athletic.