Avril Lavigne thought she was dying from a mysterious illness.

The American singer was struck down with sickness, which made her feel tired and light headed, for months before doctors diagnosed she was suffering with Lyme disease.

She'd been in Las Vegas with her friends celebrating her 30th birthday before her medical analysis and couldn't understand what was wrong.

"I could barely eat, and when we went to the pool, I had to leave and go lie in bed. My friends asked, 'What's wrong?' I didn't know," Avril recalled to People.

After doctors told her she had Lyme disease, a bacterial infection spread by infected ticks, Avril attributed it to a bite she received last spring time.

Her mother Judy moved in to take care of her when Avril's husband Chad Kroeger was on the road with his band Nickelback.

"I had no idea a bug bite could do this. I was bedridden for five months," she revealed.

"I felt like I couldn't breathe, I couldn't talk and I couldn't move. I thought I was dying. There were definitely times I couldn't shower for a full week because I could barely stand. It felt like having all your life sucked out of you."

Avril now feels "80 per cent better" and is looking forward to getting back to work. Her new single Fly is released later this month in support of the Special Olympic World Games, and will no doubt appease fans who were worried that she'd turned her back on the limelight.

"They were asking about me since I was MIA, so I mentioned to one fan directly that I wasn't feeling good. The get-well messages and videos they sent touched me so deeply.

"This was a wake-up call. I really just want to enjoy life from here on out," she smiled.