The 19-year-old, who is competing in her first major championship, managed to make the 400m individual medley final after finishing third in her heat, which was won by fellow England teammate Aimee Willmott.
"I was really nervous going into the race, I was nearly throwing up, I was so scared, but I had to get in there and do my best - that's what it was this morning," Lowe told reporters.
"It's been tough, especially back in the [Athletes'] Village, it's so overwhelming, there's so many people. With it being my first international, it was a bit overwhelming for me. I did get a bit emotional."