Processing simply means that the IRS is working on your return, it is the stage after accepted and before being approved. Here is more information on what's happening with your return
https://ttlc.intuit.com/replies/4689484
Most Federal REFUNDS are issued within 21 business days of the return being accepted by the IRS (this is not based on when you filed).
Please keep in mind that once you e-file or mail your return only the IRS has any control over it.
The IRS will notify TurboTax when your return is accepted, there are no more updates given for the next 2 stages of Processing and Approval.
You have to go to Where's my Refund to get any further information.