18-year-old Olivia Key, then 17, was like any normal girl: an active person who hung out with her friends and played sports.

But when she was rushed to the hospital with crippling stomach pain, doctors suspected that she was simply pregnant.

But that "baby bump" actually turned out to be something else entirely: a tumor in her left ovary, which was surrounded by a massive cyst.

Olivia told The Sun, “I have a small frame so for my stomach to be that big a lot of people thought I could be pregnant. I had blood tests, urine samples, checks to see if I had appendicitis and even to rule out whether I was pregnant."

The tumor wasn't the large part, though, but the cyst. According to Dr. Richard Huston, Olivia's surgeon, they had to drain "just under four litres of fluid ... before removing the cyst through a small incision." The cyst was almost the size of a watermelon (approx. 12 inches), but Olivia was lucky it hadn't leaked.

Due to her resilience and the efforts of the surgeons at St. James Hospital in Leeds, Olivia came out of the surgery in great condition. She'll still be able to have children whenever she chooses, and her speedy recovery amazed her doctors when they learned she hiked seven miles just weeks later!