Sort custom text in chronological order

I have created a calculated column which simply concatenates the week number along with the week start date and is of course stored as a text.

What I want to do is actually sort this text column in chronological order in order of weeks and year.

I cant sort it using any of my date columns as there will be duplicate values for every value in the weekNumWeekCommence column

Does anyone know a work around for this problem?

Create a week commencing column in your calendar (same logic as you have for you concat) and then sort by that.