Holmes ended years of near misses in major championships by claiming the 800m gold on Monday before becoming on Saturday the oldest woman to win the Olympic 1,500m.
"I am not going to retire, I'm in the best shape of my life," Holmes told the BBC on Sunday. "I had a burning desire to be better than I was. I needed an injury-free year to realise my potential.
"It still hasn't sunk in. It was a real tough night and I just can't believe what I achieved." Holmes said her 800m victory had given her the confidence to win the 1,500, the race she had mainly targeted before the Games.
"Winning the 800 was a big shock and that confirmed that my fitness level was good," she said. "I just had to pretend that I hadn't won the 800 and focus on the 1,500. I had a race plan and I really focused on that." Holmes said she had never doubted her ability despite her succession of bronze and silver medals in major competitions.
"My career has been such a roller-coaster but I just kept sticking in there and I knew in my heart that there was something in there for me to fulfill my dreams," she said.
More from rediff