As for the meaning, I think it's about being hit by a situation you never for saw, like a break up, and you don't know how you will make it through so you're just driving through the streets trying to figure out what is going on. The reason I think it's called "Fighting the Gravity" is because he is "fighting the gravity" of the situation, my English teacher used to always used to say that phrase, "the gravity of the situation."
As for the meaning, I think it's about being hit by a situation you never for saw, like a break up, and you don't know how you will make it through so you're just driving through the streets trying to figure out what is going on. The reason I think it's called "Fighting the Gravity" is because he is "fighting the gravity" of the situation, my English teacher used to always used to say that phrase, "the gravity of the situation."