I have been e-filing my returns from my TurboTax for years, but none of them show up in my TurboTax file on the TurboTax account. What am I doing wrong?

Did you use the TurboTax online web-based editions to file the prior year tax returns?
Or did you use the TurboTax desktop CD/Download editions installed on your personal computer to file the prior year tax returns?

TurboTax CD on personal computer

If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created.  TurboTax does not store online any returns completed using the desktop editions.

You can also get free transcripts of your federal return from the IRS - http://www.irs.gov/Individuals/Get-Transcript