Mailed in my amended tax returns for the last 2 years in Feb. 2019. My e-file status says that the IRS has accepted them but there's no record of them on the IRS site.

Does that mean that the returns are still being processed or does it mean that they haven't even received them yet? They sent one of them back 3 weeks after I mailed them for a missing signature (which I immediately signed and sent back).