A Mistake in the Wording of a Vow

I made a vow in order to strengthen myself in the performance of a mitzvah, and I intended it to last until Shabbat of Parashat Balak, but by mistake I said Parashat Korach. I remembered this after some time, and it seems that I said “until the coming Shabbat, Parashat Korach,” while in fact this Shabbat is Balak.
What is the halacha?

Shalom u’vracha 

You should perform hatarat nedarim, the annulment of vows. 

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