You should contact the IRS directly to determine the status of your 2019 return. The online lookup tools are only for 2020 returns.
You can call 1-800-829-1040. Select the option for personal tax return and follow the prompts for a live representative. The person that you speak with will have direct access to your tax return and be able to provide you with a status update.
Since call volume is sure to be high, you may wish to call or visit a local office of the IRS. You can find the office closest to you with the Taxpayer Assistance Locator tool. Once you find your local office, call 844-545-5640 to schedule an appointment.