An e-filed tax return can only be sent once. Nothing was sent if you clicked on Transmit Return again.
Use this TurboTax website to check the status of an e-filed return - https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp
Your tax return will be in a Pending state until the IRS starts accepting federal tax returns on January 23. TurboTax will send you an email when the return has either been accepted or rejected by the IRS.
