Anna Faris Says She 'Couldn't Stop Searching for Answers' After Son Jack's Premature Birth

Anna Faris Instagram

Anna Faris is giving fans a glimpse into her first few years of life after her son Jack's premature birth.

On Thursday, the actress, 44, appeared as a guest speaker during a virtual event for nonprofit GAPPS (the Global Alliance to Prevent Prematurity and Stillbirth), for which Faris serves as a board member, where she spoke candidly about giving birth to her son seven weeks early.

Faris, who welcomed son Jack with ex-husband Chris Pratt in August 2012, said that she felt "healthy and happy" during her pregnancy at 35 years old, which her OB-GYN "delicately" called a "geriatric pregnancy."

"I was surprised that for my first pregnancy I was somewhat energetic and I didn't experience any nausea. So when I woke up in the middle of the night in a small puddle of fluid, I truly didn't have any idea what to do," she shared.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Capture Pix/REX/Shutterstock

RELATED: Anna Faris Shares Rare Photo of Son Jack as an Infant to Highlight Premature Birth Fundraiser

The Mom alum said she immediately went to the hospital and felt "in shock" when the doctors told her she wouldn't be leaving without giving birth.

After a week of bedrest in the hospital, Faris went into labor and learned that her baby was coming prematurely. Jack was born at 3 lbs., 10 oz., and the actress was "briefly" able to hold him before he went into the NICU for a month.

"The day came when I got to take Jack home, and the first years were filled with doctor's appointments, five surgeries, physical therapy, a lot of laughter — because Jack was and is the most adorable cutest thing I could ever have imagined," she continued.

Still, Faris said she struggled as she was left wondering why her son was born so early.

"My mind would constantly return to the why. Why did my water break? So of course I tried to look for answers," she said. "I asked my doctor if my dream could have caused my water to break ... I asked her if the baby's nails could have torn the sack, I asked her if my sack was lacking something, if I ran too much, if I ran too little. I did gain 60 lbs — I was up to 160, and my doctor suggested at one point that I ease up on maple bars."

RELATED VIDEO: Anna Faris Says She Didn't Do a 'Great Job of Eliminating Competitiveness' with Chris Pratt: 'I Hope I've Grown'

"I couldn't stop searching. I was asking her if the geriatric thing had something to do with it, if the cold cuts that I ate… I couldn't turn off my own hamster wheel in searching for answers," she admitted.

"The truth is, in many of these cases, we have no idea why this happens... GAPPS' No. 1 goal is prevention. And in order to prevent premature births, we need answers."

Last week, the actress shared a never-been-seen photo of her son Jack as a premature baby to raise awareness for GAPPS. Another rare photo of Faris and infant Jack, now 8, was also shared by GAPPS on Instagram.

Along with Faris' GAPPS fundraiser, she and Pratt use their respective social media platforms to raise awareness about premature babies and children in need of specialized care.