I filed my taxes on January 29 and still haven't received it. I added in another tax return the next day but it wasn't amended. Is that why and will amend it get my retu

since you merely changed your copy, the IRS doesn't even know the revised return exists.  however, the missing w-2 may be the reason for the delay.  do not submit an amended return until the original is fully processed. that could further delay processing. I IRS may find the omission and adjust accordingly. certain claimed credits could also delay IRS processing. have you checked the IRs website for the status of your refund.  in any case the 21 days is just a Turbotax estimate. the IRS has already announced some refunds could take 4 weeks.  

The IRS will not accept two original returns. As tax champ @Mike9241 says, the "IRS doesn't even know the revised return exists."

Your return may also be delayed if you are claiming the Earned Income Tax Credit or Advanced Child Tax Credit. By law, the IRS cannot issue a refund involving the Earned Income Tax Credit or Additional Child Tax Credit before mid-February so those returns are automatically delayed.

Have you checked Where's My Refund? This will tell you the status of your return.