If you are using TurboTax Online, your return is saved as you work through. I would check your e-file status here to see if it was submitted, if not, sign back into your account and follow these instructions to Transmit Your Return.
If you have more than one email that has been used with TurboTax, you may need to make sure you are signing into the correct account. You can check the accounts you have here.
Another suggestion is to clear the cache and delete the cookies on your computer and reboot. Then sign back into your account. You may also want to change browsers, for example, if you are using Chrome, try switching to Firefox.