The IRS must completely process at least one of these returns for you to get a stimulus payment. They are way behind in processing returns. The 2018 return won't be processed for a long time because they are not processing any mailed returns and haven't been for some time.
You can track the status of your 2019 return if you are getting a refund using this web site:
https://www.irs.gov/refunds
See these Q&As about tax return processing: https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions
Here is where to track the stimulus payment: Get My Payment
See these Q&As for more info: Get My Payment Frequently Asked Questions | Internal Revenue Service
https://www.irs.gov/coronavirus/economic-impact-payment-information-center
