An unusually large/huge refund, usually means an entry error in one of your forms...or a double entry somewhere.
As long as you have NOT filed yet
Go back and "Edit" any form that has Federal and State withholding showing on it (usually W-2, or 1099-R or SSA-1099). Check each of the boxes on the Software form to make sure it matches your paper form value. Hitting a comma instead of a decimal point for the cents.....can result in a huge wrong entry. Also, don't double enter tax withholding....withholding already entered on a W-2 or other form, is never entered a second time on the Deductions&Credits page.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*