Absolutely. I travel a bit and take most of my "Covid kit" with me these days. A few RATs, pulse oximeter, thermometer, hydralyte, Ventolin, Symbicort, painkillers and some throat lozenges. That's all I used when I got Covid a few months ago. Pulse oximeter and thermometer is a good idea to give you an indication if you should be concerned about your vitals and seek further treatment.
If you're in a high enough risk category that you should be on antivirals at first sign of infection, you probably shouldn't be on a cruise.