08/04/2011 AT 09:45 AM EDT
Eleven days after being hospitalized in May
with serious injuries from a jet-ski accident, Sean Kingston faced a second near-death situation – a torn aorta that required open-heart surgery.
He was set to be released at the time, having recovered significantly
from the crash, when he felt a stabbing pain in his chest. After tests, he was rushed to an operating room.
"He tried to die a couple of times with us, but we refused to let him die," one of Kingston's doctors said Thursday on NBC's Today
"I had a lot of pain," the "Beautiful Girls" singer, 21, says. "But when I went to visit the surgeon [afterward], he said, 'Yo, you had a guardian angel that day.' "
Asked how it feels to be alive today, Kingston replies: "It feels great. It's a blessing. … For me to still be here, it's only God's work. I think my work isn't done. It wasn't my time yet."
Kingston, who weighed more than 300 lbs. before the accident, has been on a health and exercise kick ever since, and has dropped almost 70 lbs.
"I do the bicycle, I do the treadmill, I play basketball. But I got to keep it up and lose more weight," he tells MTV.
"It's easy to gain weight when you're in the studio. That's how it first started out, but I'm cutting all that out. I don't eat after 6 [p.m.], and then I really just do the treadmill, and that's what it is. I feel a lot better."