I contribute to a 401k through work. Does that go in under traditional IRA or is that counted when I entered my W2?

A 401(k) is not an IRA.  Enter amounts shown in box 12 of your W-2 only in box 12 of TurboTax's W-2 form, nowhere else in TurboTax.

No a 401K is not a IRA.  Only enter it from your W2, nowhere else.  It has already been deducted from the wages in box 1 and you can't deduct it again.