The IRS is currently not processing any mailed returns (regular or amended) and hasn't been for some time. An amended return in normal times takes 16 weeks to process and will take a lot longer with this pause in processing. The IRS has not indicated when they will start processing mailed returns again. It is too soon to worry about the status of your return.
When they do start processing it, you can track the status using this tracking web site:
https://www.irs.gov/filing/wheres-my-amended-return
