I think its about someone who really has feelings for someone and its come really suddenly "watch me descend into a feeling thats overwhelmind me" and can't really understand what shes feeling "I finally stopped making sense"
"where we;re heading, tripping, ugly, theres no heading back" means that she doesn't want to fall that far and is scared, but theres nothing she can do about it.
Over the course of the song though she is like coming to terms with it "for the record when im with you things are looking better"
Etcetcetc.