The 'Price Tag' singer - who supported the US star before rising to fame in her own right - explained having never touched drugs in her life, she wasn't aware of what she was doing when she ate a cannabis-infused cake in the Dutch city, and ended up being rushed to hospital.
She explained: "I accidentally ate a whole hash cake in Amsterdam while I was on tour with Chris Brown. I had to call an Ambulance because I started convulsing.
"I called my mum and she was like, 'I'm glad you did it because you'll never do it again'."
The 22-year-old star - real name Jessica Cornish - also admitted she thought her "life was over" when, at the age of 18, her first record deal fell through and she suffered a minor stroke.
Jessie added to Style magazine: "It was like my life was over, but my mum told me, 'When one door slams in your face, it means there's another one around the corner, waiting to be opened'. And in the end, it was a golden ticket in disguise."
While the raven-haired beauty is open about being attracted to both men and women, she revealed she has only been in love once in her life.
She said: "I've been very open about the fact I've been with girls and boys, but I've only been in love once and it's an amazing feeling."