If there's nobody to get enlightened, why bother?

It seems the goal of Buddhist practice is to become an Arahant - someone who won't take a rebirth, and therefore will be eternally relieved from suffering. But WHO is this someone who doesn't get reborn? I mean if there never was a self to begin with, then who exactly achieved Nirvana? Seriously, this line of thought is screwing up my motivation. All this work, just so someone who doesn't exist yet, and never will, doesn't have to suffer. Buddhism doesn't promise relief from suffering in the current lifetime, in fact it guarantees us we'll all die, and most of us will suffer from sickness and old age (not to mention loads of other suffering), but it promises an end by not taking a rebirth - but the whole concept of rebirth is made utterly confusing by the concept of non-self.