The 38-year-old singer announced her split from the pastor in an Instagram Stories post Friday, the same day as the release of her single "Fearless."
"I still remain fearless," Williams wrote in the since-deleted post, according to E! News. "I guess I still remain single! Things didn't work out."
"The healing that needs to take place is a must! I don't wanna destroy another relationship. Blessings to him, his family and ministry. #FEARLESS," she added.
Williams and Johnson got engaged in April after a year of dating. Williams told People in October she and Johnson were in individual and couples therapy after she broke off the engagement twice during a depressive episode.
"There was a period of time where we did not know if we were going to make it down the aisle," the star said.
"I'm absolutely thankful for Chad. I'm so grateful and thankful for him. It's not about marrying him, it's to do life with him. I feel like I found someone to do life with," she gushed.
Williams confirmed in a post in July that she sought help for mental health issues this year. She said she was feeling happy and healthy after working with healthcare professionals on her well-being.