Her family confirmed Campbell died on December 29 in Portland, Oregon. The results of her autopsy are still unknown.
Campbell had retired from her acting career to become a naturopathic physician. Wessling told the outlet at one point Campbell went into a bathroom and never came out, leading her aunt to check on her and find that she'd collapsed.
"A true adventurer in every sense of the word, Jessica packed a staggering amount of experiences into her tragically short lifetime", Wessling says on the GoFundMe page. News has reached out to the Multnomah County Medical Examiner. In addition, she made a few TV appearances, including on Freaks and Geeks.
Prior to her death, Campbell had been complaining about congestion and said she thought she was getting a cold.
She would go on to guest-star on NBC series Freaks and Geeks and 2001 movie The Safety of Objects with Glenn Close, before quitting acting and living a normal life.
In the film, she played Tammy Metzler, the sister of school jock Paul whose girlfriend leaves her to start seeing Paul.
The death was unexpected and her cousin Sarah Wessling spoke to TMZ about the tragic circumstances. "I'm sending all my love to Jessica's family and loved ones", Witherspoonposted on Twitter.
Campbell rose to fame in the critically acclaimed film Election - which also featured Matthew Broderick and Chris Klein - and earned an Independent Spirit Award nomination for Best Debut Performance. "Heartbreaking news. My deepest sympathy to her son and the rest of her family".