Several factors can impact the timing of your pay.
The most common cause is that your timesheet hasn't been submitted and is still sitting at the created stage awaiting you to click the submit button or it hasn't been approved on time.
We strongly recommend that should you not receive an email notification by lunchtime on the day before your scheduled pay date, give your timesheet approver a gentle reminder to log in and approve your timesheets.
Notification emails are auto-generated and can sometimes end up in the approver's junk/spam folders so they may not have looked in there to see if a request to approve a timesheet notification has been issued to them.