The German international, 27, arrived in the summer of 2016 having suffered a dislocated kneecap during his final few weeks at Borussia Dortmund, delaying his debut until the September of his debut season.
And having fought his way back to full fitness, he played just 17 games before rupturing cruciate knee ligaments and spending eight months on the sidelines.
But he returned to the side in September as City beat Watford 6-0 at Vicarage Road and has since played 38 times.
With his influence steadily increasing, he says he is relishing being a regular in the team.
“It feels great now to be back and part of the team, to play my own individual role, which is also important,” he said.
“I’m enjoying it and I’m very happy. It’s a very happy period for make in my life and my career again.
“I’ve been through a lot of ups and downs in the past, so obviously it feels great to be back and to train and play.
“I can’t even compare it [to last year during the injury]. It feels so much in the past. I don’t even want to think about it.
“It’s a big change now for me, a very happy change. It feels great, I’m enjoying it a lot and obviously I’m doing everything I can to stay fit.
“I just think about now, about being part of the team, about training well and playing well, about doing what the manager and the staff want me to transport into the team.
“I have my own impact and during the last months I was still on my way to my best.
“Now, I feel nearly or already there, and I am having fun and I’m happy.”
Gundogan played a key role in City’s recent League Cup triumph, appearing in all six matches en route to the trophy.
It was City’s first piece of silverware under the tutelage of Pep Guardiola, a watershed moment for the Club in its current phase.
Gundogan says he was delighted to be a part of the success but believes only by competing with Europe's elite teams will this City side reach its full potential.
“Just a few days before the final we lost against Wigan [in the FA Cup],” he said.
“This loss made the League Cup final even more special and important for us. I thought the pressure was even higher for that game.
“Fortunately, we won it and we were very happy that we were able to gain our first trophy early in the season. That’s now in our hands, no one can take it away.
“It feels great. But this is just the beginning, I think.
“We are still on a road – a good way, I think, with the way we play – to come into that elite of clubs in Europe.
“I wouldn’t say we are there. We need to compete with teams like Madrid, Barcelona, Bayern Munich, Juventus…the biggest teams.”