Thank you for clearing that up.

The reason behind my confusion was that usually when people use "next" against a day in the week, it refers to the day in the upcoming week unless it is used on the same day as the one being used in the sentence. For example, if it's Sunday today, and I say "next Sunday", it means I'm referring to the one that comes next, but, if it's Wednesday, or any other day in the week, and I say "next Sunday", it can also mean the Sunday that comes next week but not the one coming this week since according to International ISO 8601 standard, a week starts on Monday and ends on Sunday. However, for some countries, Sunday is the starting day of the week, so the "next Sunday" thing could cause confusion sometimes.