Can I get a copy of the 1040x I filed last year?

You have a couple of options:

for paper copies from the IRS:

 https://turbotax.intuit.com/tax-tips/tax-planning-and-checklists/video-how-to-recover-past-tax-retur...

Or, from TurboTax:

https://ttlc.intuit.com/questions/3404575-how-do-i-access-my-prior-year-2016-return