If I have to identify the most important moment of this crisis, it was just before a Juventus-Reggina match in February 2004. It was an evening game. We were six points off the top of the table. There were 13 games left in the season, so anything could still happen, but there was an air of negativity, as if the season was already over. We had just had two crazy and very different games. In our previous league match, we had conceded four goals to Totti and Cassano’s Roma, while in midweek we had won the Coppa Italia semi-final against Inter at San Siro, on penalties. Although we were still in the running in the Champions League and perhaps even a little in the league, inside me I was certain that in that season everything was lost.

It was a classic winter Turin evening, wet and cold, and the stadium was half-empty. The speakers played a song that I only heard as an annoying buzz. During the warm-up I prayed and performed my usual pre-match routine, but it felt as if something was wrong with my muscles. After two minutes I put on my gloves, I stood in the goal and I realised that I was struggling to breathe. I stood there, staring at the pitch, and I felt slightly dizzy. What scared me, however, was the tightness I felt in my diaphragm, between chest and stomach, as if I had been hit.

[Ivano] Bordon, the goalkeeping coach, looked at me and realised that something was wrong, and while I tried not to look at him because I didn’t want to scare him, I kept going. Yet I was really struggling to breathe and I felt a sense of fear that I did not understand. When you have a panic attack, you don’t know you’re having a panic attack. When you have a panic attack you think you’re going to die. I couldn’t deal with that situation, or focus on my routines, because I didn’t know what was happening to me, so I went up to Bordon and told him to get Antonio Chimenti, the reserve goalkeeper, to warm up because I wasn’t feeling well.

I sorted out my mind: “Come on, Gigi,” I said to myself, and I gave myself strength: “When the game is over you can stop playing football. Just take on this hour and a half and then say goodbye to it all.” And while I was muttering to myself, I could see Chimenti warming up.

The first thing I thought was that if I didn’t play that game against Reggina I would never play again and would become a kind of ghost. I was young, and it was not clear exactly what that sense of unease was. I interpreted it as a lack of courage. This was a sense of fear that the Buffon I had built up in my mind could not afford. In terms of my self-esteem, for how I want to live my life, for how I lived, I was anything but weak. So I played a trick on myself. Then it would all come to an end.

I did a minute and a half of the warm-up and went to get changed, and as I returned to the pitch I felt that I was breathing a little easier, and that feeling of unexpected well-being caused an adrenaline rush. Adrenaline stops your panic causing a shortness of breath. The effect doesn’t last long, but it is what you need for the game. So much so that we entered the pitch and, after 10 minutes I made a save from a difficult free-kick and, at the end of the first half, one of my best saves of the championship, from Ciccio Cozza, while we were still at 0-0. The Reggio playmaker was one on one with me, and on the edge of the six-yard box he tried three tricks. I stood up and blocked his lob with one hand. We won 1-0, and the save from Cozza gave me an important push in order to finish the game.

The next day I realised that I would have to learn to live with this discomfort. I couldn’t always be on the edge of disaster searching for some extra bursts of adrenaline in order to play. The news leaked out that something strange had happened to me, but it wasn’t clear exactly what. Some of my teammates asked me about it, and even just answering those questions felt hard, because I didn’t know what to say.

Panic. That word was not part of my vocabulary. For a couple of months I had been sleeping badly, I would wake up soon after falling asleep and negative thoughts were running through my head: I would disappoint my parents, my fans, I was about to throw away my career. “Someone who has been lucky enough to live this life.” But it wasn’t luck, I have earned this success. “Someone who earns a lot of money and is successful just because you kick a ball.” But kicks are not important to me, I’m a goalkeeper, I dive, I get injured, I hurt myself, I am covered in cuts, bruises, bumps and swellings.

Some of these thoughts told me to try not to think too much. Others advised me to try to hide this negativity. But even if I were to try – metaphorically – to put these thoughts on a paper boat and let them glide down a river, they would return in ways that were even more insistent and insinuating. I was afraid to go out, to talk to the people who loved me. I woke up groggy with a tiredness that affected my body, my legs were lacking in energy and I began to lose a sense of certainty in my movements.

I talked about this with my closest friends, and then with Juve’s doctor, Dr Riccardo Agricola. To his questions, my answers were: “Stretched out”, “I can’t stand up”, “I’m really in the shit now”. I tried not to take myself too seriously, to laugh a bit at myself and my discomfort. But it wasn’t a healthy kind of self-irony, I was just hiding that feeling of darkness from myself.

One day Riccardo said something that struck me, during one of my long monologues on this illness that I could not name, the weakness I felt, on feeling drained: “Gigi, it could be depression.”

Saved by Gianluigi Buffon is available now from the Guardian bookshop.

In the UK and Ireland, Samaritans can be contacted on freephone 116 123, or email jo@samaritans.org or jo@samaritans.ie. In the US, you can call or text the National Suicide Prevention Lifeline on 988, chat on 988lifeline.org, or text HOME to 741741 to connect with a crisis counselor. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at befrienders.org