Sunday's 3-1 defeat against Tottenham meant Swansea have now gone eight Premier League games without a win, picking up just three points from a possible 24. They lie just three points above the drop zone.
A lengthy injury list including Michu, Michel Vorm, Jonathan de Guzman, Jose Canas, Pablo Hernandez, Nathan Dyer, Garry Monk and Jonjo Shelvey has not helped, but Williams feels Swansea should still have performed better then they have.
"If I could I'd stop it," he said of their form. "We're working hard, we're talking a lot about it.
"We have been playing against some top teams, but still teams we expect to get something out of. That's not an excuse.
"We also have injuries to key players maybe but again that's not an excuse.
"You can see in the way we are playing that confidence isn't a problem, it doesn't feel that way anyway, we still getting on the ball a lot, and when teams are lacking confidence they tend to shy away from it.
"We're trying to give it a go but I can't work out what's going wrong.
"I've never conceded so many goals in my Swansea career but we're not giving ourselves a chance.
"Maybe if Wilfried (Bony) scores and we go one up it could have been different. I take full responsibility."
Swansea's winless run has included fixtures against Everton, Chelsea, Manchester City, Manchester United and Spurs.
Their next four games are against Fulham, West Ham, Cardiff and Stoke, and Williams admits it is a string of fixtures which could define Swansea's season.
He said: "It is crunch time, we said how important the Christmas period was for us and we didn't really perform and now it's another crucial period.
"If we have a few good results in the next four then we'll be okay but if we don't then the pressure is on. But this is football and sometimes it happens and you just need to get through it.
"I'll be down over the next few days just like the other boys and the fans. But we've got to pick ourselves up and go at it again.
"We have played some tough teams, but these aren't rubbish teams we're going to be playing against, they are teams that are scrapping for their lives as well.
"Now we've left it so that it is a must to get points from these games, so it's going to be tough but its something we're highlighting to try and get points out of."