It depends if you have taxable income after the standard/itemized deduction was applied. if so, there is a tax liability assessed in your return that may be more than your W2 withholdings. Also if you had self-employment income, there may have been your share of self-employment taxes that you needed to pay.
Also, if you received more income than was withheld, you may have received refundable credits such as the Earned income Credit.
Here is how you can look at a snapshot of your return.
Anyway, these a just a few ideas that may answer your question without actually looking at your tax return.
you want the federal withholding back?
No, in that case, IRS would get nothing and the country would really be broke.