I e-filed my taxes all wrong I left out one of my dependants and forgot to put his w-2 how do I fix this mess? I feel like such an idiot!

You will file amended tax return. For amending your tax return, you must file IRS Form 1040-X. Column A is what was on the original return, Column C is what should have been there (that is corrected amounts) and Column B is the difference. Complete these columns and then refigure your tax.