Do you ever feel as if you are in a race, galloping along with rivals alongside you, jumping over obstacles and trying not to tire? It's perhaps not surprising that your 'career' should feel like that, because that's what the word originally meant.
In the 16th century, a 'career' was a short gallop by a horse, or a racecourse. Later, it meant any continuous course of action or progress, before, in the 20th century, settling down to mean one's professional life. The word came into English from French, and originates in the Latin word carrus, which meant wagon: things move faster nowadays.