Her treatment regimen has included multiple antibiotics and ample rest.
“I'm about halfway through my treatment,” the Canadian singer said in an interview with ABC News’ Jesse Palmer. "I'm doing a lot better. Seeing a lot of progress. ... I'm just really grateful to know that, like, I will make [a] 100 percent recovery."
Lavigne, 30, said trying to get a diagnosis was the worst time of her life.
“I literally became bedridden last October,” the “Complicated” singer said, adding that she saw multiple specialists who failed to get to the root of the problem. “They would pull up their computer and be like, ‘Chronic fatigue syndrome.’ Or, ‘Why don't you try to get out of bed, Avril, and just go play the piano?’ It's like, ‘Are you depressed?’”
Lavigne said she would wake up with night sweats and felt as though she had the flu.
“This went on and off for a month,” she said. "And I saw my doctor right away, got blood tests, got swabbed, and they didn't really know what was wrong with me."
It wasn’t until two months into the symptoms that she said she suspected Lyme disease.
“I started going to other doctors and, like, specifically telling them and asking, like, ‘I have Lyme disease. I know I do. Can you check me?’” she said. "Then I finally figured out, 'Find a Lyme specialist.'"
"And the thing is, when you're a specialist, you also really know the disease inside and out and you can diagnose their symptoms," Lavigne said.
After getting the diagnosis of Lyme disease, which Lavigne believes she got from a tick bite last spring, the singer was bedridden for five months in her Ontario home.
Lavigne, who is married to Nickelback frontman Chad Kroeger, said her family and fans have helped her through her ordeal.
Many fans, she said, made videos and sent her letters and posters and other items to show their support.
“I sat there in my bed and I watched the videos and, like, did exactly what I'm doing now. I cried through the whole thing,” she said, laughing. “Honestly, I felt very, very loved. And it sounds silly saying it, but I really truly did feel my fans through the process.”
She took the opportunity to share encouragement to others with Lyme disease.
“There is hope. Lyme disease does exist. And you can get better,” she said.
She called this period her “second shot at life,” adding: “I really just want to go out there and truly do what I love. So I'm so excited for life after this.”
Lavigne is set to perform her song, “Fly,” on July 25 at the opening ceremonies of the 2015 Special Olympics World Games next month in Los Angeles.