If your income is consistent, then double check that your withholding was also consistent to see if this year varied from last year significantly. The other thing that may have happened is if your children turned 17, then your child tax credit moves from $2,000 per child to $500. With two kids, that would have swung your refund by $3,000 all other things equal.
To combat this, you may want to revisit your W-4 withholding to update the ages of your children. If it's not an issue with the children turning 17 or a change in your withholding, please reach out to TurboTax, and we can look into the detail.