ABU DHABI, United Arab Emirates (AP) — Lewis Hamilton says he “massively underestimated” how big a toll his decision to leave Mercedes for Ferrari would take on his relationships with the team where he won six of his seven Formula 1 championships.

Hamilton’s move to Ferrari for 2025 ends the most successful partnership between a driver and a team in F1 history. The decision was announced in February and has overshadowed an often-difficult season with Mercedes that has yielded two wins but some poor recent results.

“I anticipated it would be difficult, but massively underestimated how difficult it would be. It was straining on the relationship very early on, took time for people to get past it,” Hamilton said Thursday, Dec. 5. “And then just for my own self, it’s been a very emotional year for me and I think I’ve not been at my best in handling and dealing with those emotions.”

Speaking ahead of his final race for Mercedes on Sunday at the Abu Dhabi Grand Prix, Hamilton said he’d been left with “loads of bruises” following a game of paintball with some Mercedes colleagues shortly after his move to Ferrari was revealed. “People went in on me that day,” he said.

Hamilton added that he was working on how he handles difficult personal situations following some of the strain in his relationships this year.

“I think you’ve all seen the worst of me and seen the best of me, and I’m not going to apologize for either because I’m only human and I don’t always get it right,” Hamilton said. “I definitely would say this year has been one of the worst in terms of handling that from my side, which I work on trying to be better at. But I hope the good and the highs far outweigh the negatives and how I’ve handled it or behaved.”