The way I see it, either there is afterlife, in which case I'll find out in due course; or there isn't, in which case when I die I'll cease to be and certainly won't care.
While I can't claim with any degree of certainty that there isn't something after death, however, it seems to me that any sentient race would invent some sort of heaven as a means of coping with their own mortality over the course of their evolution; I find that the chances of this coping mechanism actually being true are rather low.
In short, nobody can claim for certain whether you keep existing in some form after you die, but I think there's a high degree of probability that every religion on the planet is wrong on the matter.