Doom is useful. The reason you stockpile food or grow a crop in spring is to avoid the doom that would come winter, if you didn't. Fearing a possible bad future is fairly fundamental for survival.

I assume there's some significant hard-wiring for this type of emotion, with some people having a different baseline for their sensitivity to it. I also suspect the environment might push regional genetic population to have different sensitivities, depending on how harsh/unstable the environment is. I say "unstable" because I see doom as anxiety about the possibility. For example, in a region with a consistent harsh winter, doom has less use because piling food up is just routine, everyone does it, it's obvious. But, in an unstable environment, with a winter that's only sometimes harsh, you need to fear that possibility of a harsh winter. You're driven by the anxiety of what might be. You stockpile food even though you don't need it now: you're irrational in the instantaneous context, but rational for the long term context. It's a neat future looking emotion that probably evolved closely with intelligence.