I looked in the mirror, and what did I see?

I have a namesake who is more than a namesake: a doppelgänger. Not only do we have the same job and therefore the same skills, but we also have the same talents. Throughout my life, I have felt special because I can do a few things that other people cannot do as well. (I cannot do a lot of things that other people can do, like rollerskating, but that's beside the point.) Yet there she is—the Other Beth.
I was hired first, but whilst I was suffering from mononucleosis and working short hours at home, she took all of my special projects and became team lead. I don't mind that she finished my projects, because I was too sick to finish them. However, all of the new projects that would have been mine now go to her, as she is in charge of delegating; her finished projects are not any better or worse than mine, just exactly the same.
When we are both in the office, uneasy air vibrates between us as if two Beths cannot exist in such close proximity. I am the superfluous shriveled remains of her conjoined twin.
I irritate her as much as she irritates me. Our smiles to each other are more paste than pathos, and she makes a point to contradict our boss when he suggests that she give me more responsibilities.
Were life like literature, one of us would kill the other and restore balance to the universe.