Explain me the meaning of a sentence
I have a passage from a novel:
The governor was a man who rarely gave orders because he rarely needed to; he was used to having his will obeyed. However, this was an order, and there was no way out of it. Even if it was a trap, I now had to comply. So off I went, with the governor’s money in my hand, to buy five grams of cocaine.
I can't understand this piece: "so off i went".
Thanks for helping in advance.