Few financial surprises rattle the nerves as quickly as realizing something is amiss in a tax return already sent to the IRS. Maybe an unexpected W-2 surfaces weeks after filing. Perhaps a missed business receipt or the fast click of "single" instead of "head of household" sends you spiraling, even before any official notice lands in your mailbox. The moment doubt sets in—whether triggered by overlooked credits, uncertain deductions, or those ambiguous IRS letters—it can feel