The 'Father Figure' singer was hospitalised in Vienna after falling sick with the illness back in November, and has said that he "dodged a bullet".
"I had to relearn to walk due to muscle atrophy. I just woke up kind of like this feeble old man. I guess all I can say about it is it was a horrible experience," he told Chris Evans on BBC Radio 2.
"It was downplayed because I didn't want to worry [anyone], or to have the press clamouring around the hospital. It would have been like a death watch."
On how close he was to dying, he explained: "It was three weeks touch and go, on several occasions it was very close.
"When something like that happens, it takes a while to feel that life is safe again. I've lived with a lot of anxiety since."
Michael also explained that he became worried about death after following a news report on Whitney Houston's passing.
"I was watching footage of Whitney Houston being wheeled into an ambulance. I said 'change the channel'.
"It would have been freaky if Whitney and I had died within six weeks of each other. We both became big at the same time, we worked together."
He added: "I dodged a bullet. I appreciate how lucky I am to be alive."
George Michael's new single 'White Light' will be available to download from August 12. The song documents his near-death experience, and features a coin toss to determine whether he lives in the video.
Watch the video for 'White Light' below: