The blonde beauty revealed that she started to suspect she had the disease back in October, and after numerous doctors visits, she was diagnosed with the illness.
"I'm about halfway through my treatment," the Canadian singer revealed. "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."
"I literally became bedridden last October," the 30-year-old said, while also explaining that she saw multiple specialists who failed to properly diagnose her. "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 also revealed that her flu-like symptoms started with night sweats. "This went on and off for a month," she continued. "And I saw my doctor right away, got blood tests, got swabbed, and they didn't really know what was wrong with me."
That's when the "Complicated" singer started to do her own research and came the conclusion she was suffering from Lyme disease -- which she believes she contracted from a tick bite last spring.
"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 explained. "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 added.
Luckily, the pop star has had a strong support system by her side -- from her hubby Chad Kroeger, to her family and even her fans.
"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, with tears in her eyes. "Honestly, I felt very, very loved. And it sounds silly saying it, but I really truly did feel my fans through the process."
"There is hope. Lyme disease does exist. And you can get better," she explained. "I really just want to go out there and truly do what I love. So I'm so excited for life after this."