The 24-year-old singer-songwriter was the event`s big winner scooping awards for best album, best British female solo artist and best breakthrough act, according to Telegraph.co.uk.
However, in the excitement of receiving the accolades for her Rockferry album, the Welsh star became the latest celebrity to turn the airwaves blue at the annual ceremony.
By the time she collected her third award, the singer was visibly choked with emotion and said that making music was sometimes a struggle.
She said: "I`m not going to lie to you, it`s really not ------- easy. It`s hard. It`s really hard."
Speaking after the awards ceremony at London`s Earl`s Court, Duffy added: "I was wondering this morning what I would know tomorrow and it seems that I have come away feeling happier than I could have imagined.
"It doesn`t really matter what you achieve - in the end you`re still the same person. I still have the same problems, I still wake up with a headache. Nothing changes."
Rockferry was the best-selling album of 2008 and shifted 4.5 million copies around the world.
She beat Adele, Beth Rowley, Estelle and M.I.A. for the best female solo award.
She said friends and family in her home town of Nefyn had organised celebratory pub crawls and her aunt was holding an open-house party.
Despite Duffy`s slip, the glitzy ceremony passed without controversy - unlike previous years.
Sharon Osbourne repeatedly swore at last year`s ceremony and was involved in a minor tussle with Vic Reeves.
Comedian Russell Brand caused controversy while hosting the 2007 Awards ceremony, over comments about the Queen`s "naughty bits" and a fatal friendly fire incident involving a British soldier killed by American armed forces in Iran which led to more than 300 complaints to ITV.
In 1996, Pulp frontman Jarvis Cocker invaded the stage and waved his bottom at Michael Jackson in protest at his Christ-like performance of his single "Earth Song"
