Track weekly overtime worked and available ytd

We are having problems with a spreadsheet where OT hours worked each week are input and totaled ytd. Additionally, the overtime available each week is automatically calculated from this initial input with formulas and totaled in a ytd column.

When we sort based on the available OT ytd (the last column), the formulas are no longer referencing the correct cells. We tried using the $ options, but that did not seem to help or are using them incorrectly.

Attached is our draft spreadsheet. Any ideas or assistance is appreciated.