Thought I'd be able to do at least reasonably well.
Well I would say that given that you didn't vote for yourself; that you are the #3 candidate on the PLP ticket (and indeed you voted to put yourself in that #3 spot); and that you haven't made a very visible campaigning effort for votes - it could be perceived that you haven't been entirely concerned about winning a Senate seat, which may be being reflected in the votes so far.
The bolded part is essentially what did it. Even the no-shot-in-hellers voted themselves #1, which puts them in front of you almost by default.
True but I realized that I had less of a chance than Sensei and Earl and that they best represented my views.