Fear of losing gravity?

I have a weird phobia, like whenever I get too close to a really tall vertical object like a skyscraper or TV antennae I feel like gravity is gonna give way and I am going to be sucked into the sky like mighty mouse but not because i can fly, but because space sucked me away. I know there is a fear of gravity but why is there no phobia for a fear of losing gravity? It's not a fear of flying, I already know this, it's definitely a fear of losing gravity. When I was in chicago last year with my family I got too close to the sears tower and felt like I was a goner. Like I literally felt like gravity was going to end that moment and I was going to get sucked away like nothing. It's a scary feeling. More insight anyone? Please?