The IRS is not working on mailed returns now---and an amended return can only be filed by mailing it in. Under normal circumstances you would be able to see something about your mailed in Form 1040X after about three weeks, but that is not the case right now. The usual 4 months for processing an amended return is going to take longer. Sorry.
Per the IRS website IRS Operations During COVID-19: Mission-critical functions continue: The IRS is not currently able to process individual paper tax returns. If you already have filed via paper but it has not yet been processed, do not file a second tax return or write to the IRS to inquire about the status of your return or your economic impact payment. Paper returns will be processed once processing centers are able to reopen.
If you mail a tax return (or a payment) to the IRS, it is a good idea to use a mailing service that will track it like UPS or certified mail so you will know it was received.
TurboTax will not know anything about your amended return, and nor will TT know that you put your 1040X in an envelope and took it to a mailbox. TurboTax does not get updates on mailed (or e-filed) returns.
When the IRS finally opens its mail and begins to process mailed returns you can check the status on the IRS site.
This was about the time the IRS closed their offices and quit processing mailed returns. They may have opened your return if you were able to confirm that they received it and then didn't go ahead and process it because of the closure. They are way behind processing returns and many offices are still not open.
All you can do is track the progress on the web site: https://www.irs.gov/filing/wheres-my-amended-return