The 28-year-old made his comeback during New Year`s Day`s defeat at Burnley after eight months out following three operations to repair a disc bulge in his back.
Williamson`s recovery should have been much quicker but he suffered complications with the first procedure, which saw the operation wound become infected and led to two further operations.
And after going under the knife three times in such a short space of time, Williamson was forced to consider his future.
"After the third operation I had in my mind that if it didn`t solve the problem I wasn't keen on having another operation," Williamson, who is set to start for the Blades against Aston Villa in the FA Cup on Saturday, said.
"I am 28 and I have had three operations on my back so I don't want to keep going at it. I love football but I have to think of my life as well. "My back feels strong. I just want to stay in the team now, I have to do my best to keep fit and stay in the team."