I've randomly developed a fear of heights?

so I was never afraid of heights before, when i was small i took gymnastics and was the only one in my class who would climb a rope to the very top of the building .. i loved climbing to the top of things. Now i'm 19 and I would say in the past year and a half I have developed a fear of heights out of nowhere! sometimes even walking up stairs with spaces in between them makes me feel sick and gives me jello legs, I used to love ferris wheels and now I cry and have panic attacks. There isn't anything that has traumatized me to make me become scared all of a sudden so I was wondering if anyone knows why this has happened or have experienced anything similar?