The Portuguese midfielder spent the summer uncertain over his next move before deciding to return to Hamburg SV, where he had already spent the previous season.
Vieira admitted the situation was difficult while his future remained unresolved, particularly with his Arsenal contract entering its final year.
"Absolutely. I'm doing very well here, and I think everyone can see that. The summer wasn't easy for me. For a long time, I didn't know where my path would lead. Everyone knew that I was going into the final year of my contract at Arsenal. In the end, I chose Hamburg. I was already here last season, I enjoyed every moment and realised that this is the perfect place for me," Vieira told Sky Sport.
The midfielder said the final stages of the transfer were particularly tense as he waited to find out whether the move would be completed.
"Yes. The last two or three days were pretty intense. I was already a little nervous because I didn't know if everything would actually work out. But in the end, everything went well. Now I'm here and I'm very happy about it."
Vieira also revealed that Hamburg coach Merlin Polzin remained in regular contact with him throughout the summer.
"At the beginning, he mainly told me: 'Enjoy your holiday. Spend time with your family. Afterwards, you can think about your next step.' At the same time, he made it clear to me: 'You know that we want you here.' After that, we were in contact almost every week and talked about how things were developing. At some point, we found our way back together."
The midfielder also credited Hamburg sporting director Claus Costa for helping make the transfer happen after travelling to London to meet him and Arsenal.
"Very important. Claus had a big influence. He came to London, we had a meeting there and put everything on the table. We talked about how we could find the best possible way for me to move to HSV. At some point, it was no longer up to me, but the two clubs. They sorted it out, and now I'm here."
Vieira said his decision was driven by the experience he had during his previous spell in Hamburg.
"Actually, everything I experienced last season. The club, the people who work here, the stadium, the fans. They always support us, whether we play at home or away. I'm happy here. I feel that the people at the club and the fans like me. When you're in a place where you get that feeling, it does a lot for you. It gives you confidence."
For Vieira, the decision to leave Arsenal and return to Hamburg was ultimately about finding the right environment to continue his career.