I was able to purchase an at home iHealth antigen test from my CVS. However, you must also purchase the proctoring service separately online if you need the test to be valid for the cruise.
I plan to have this as my backup if I'm unable to get a rapid test done in person and have to resort to a PCR which may or may not get back in time (I have noticed less and less of the drugstores in my particular area are offering rapid NAATs or antigens).
I chose iHealth over eMed because I can get the test right at the corner drugstore, they are reimbursed through my insurance (they only cost $20 for a two pack), and if I don't need the proctor service, then I'm not out any extra money. If I need it, I can easily go online and add it for $25pp (and they seem to have tons of next day appointments available).
Just wanted to toss out another option in case you find it helpful. Enjoy your Med cruise!!!!