The Junior Senator from Massachusetts appears to be having trouble adjusting to being a nobody again. He'll get used to it because deep down inside he is a nobody.
He's just sick about not having all those celebs tripping over themselves to fawn over him while he acts like a teenybop groupie, being the headliner amongst roaring anti-Bush crowds, and not having all those secret service men making him feel like the big somebody he believes he is. I imagine how he's feeling now is akin to what has-been stars feel like.
At least he no longer has to be "amazed at the number of people who want to introduce themselves to you in the men's room."