"I had hoped I could continue," the actress tells PEOPLE. "I just got weaker and weaker"
Credit: Evan Vucci/AP

It was a 21-day fast that fell nine days short. But in the final hours, Mia Farrow knew, “I couldn’t do it.”

“I just got weaker and weaker,” the 64-year-old actress and humanitarian tells PEOPLE of Friday’s end to her hunger strike to draw attention to Darfur. “I lost about 13 lbs.”

Though she was determined to continue, she was instructed by her doctor to immediately stop due to severe health risks. “My doctor visited on Wednesday and told me to have sugar immediately because my blood sugar count dropped,” Farrow says. “He said I could go into seizures.”

Struggling to maintain energy and strength, she eventually found it too difficult to stand up. “I got up out of bed and went down to my knees. My muscles were aching,” Farrow said.

Farrow, UNICEF Goodwill Ambassador, began her hunger strike on April 27 to protest the Sudanese president’s expulsion of 16 aid agencies in Darfur, causing a million people at risk of starvation.

“I was very disappointed,” she says. “I am a very stubborn person and very determined. I had modified my goal from 21 days and really hoped that I would reach my goal of fasting for 16 days, which is the number of aid agencies expelled.”

During the past 12 days, Farrow stayed closed to her bed and passed the time listening to classical music and reading books. “I watched Schindler’s List all the way through. Then I cried and cried,” she says. “I got very emotional at the drop of a hat. I would perk up when my granddaughter came over. I’d play with her a little and that was great.”

Slowly back to eating food again, she has been eating oranges and drinking soup to regain her strength. “I feel so much better with the food in my system. I feel so much more peaceful,” she says. “While a million people in Darfur are facing starvation, I have the ability to end my fast. These people do not have that option. If I have any use at all, it is to speak for them.”