After a night out in London in April 2014, Lee, 32, got behind the wheel of a friend's car and was pulled over by the police.
Speaking to the Mirror, the Blue singer said: "I wasn't thinking about my safety at all. I'm just lucky I'm not dead and that I didn't kill anyone else."
But Lee admits that, at that point in his life, he didn't care about anything and was 'waiting for something to happen'.
He continued: "During that time people I worked with said I was broken and like a ghost. I didn't give a s***. I just felt so much pressure, like everyone hated me."
Lee checked into rehab after the drink-driving incident and he insists it will not be happening again.
"This may not be the first time I've been done for drink driving but I was much younger before," he said.
"People forget I was only 16 when I started in Blue. It's not going to happen again. I still see my counsellor – he's a lovely man – and I'm finally happy."
But last week it was revealed that Lee has a cyst in his throat which could spell the end of his singing career.
Although the cyst could potentially ruin his voice, Lee said that he was relieved to discover it wasn't cancerous.