Deryck had to be held up by two women during a walk in Los Angeles.
On Friday, Deryck revealed he'd been laid up in a hospital bed for a month, and confessed on his blog...
There's no word as to why now was the right time to make the official change.
Earlier this year, Whibley made headlines for appearing at a Tom Petty concert in Los Angeles and surprised many with his rather bloated appearance.
An unidentified witness to the wedding told the CPA, "It was a short, classy ceremony with the sound of helicopters droning overhead carrying photographers trying to get a shot of the newlyweds, and most of the people there were friends and family. They both seemed really happy." Sum 41 drummer Steve Jocz was Whibley's best man.