Saliva

I think this song is about breaking up with someone, and missing them so much that you just can't stop thinking about them.

"I drive alot 'cause I can't stop thinking about her"

And maybe they realise that, even if the relationship isn't perfect, they should try to get back together again?

"I'll be yours, you'll be mine. It'll be fine."

That's just my opinion though.

I really, really like this song. ;D