Not just this but anything. When something bad or things I don't like happen, staying negative and complaining won't really get anywhere (for me at least). I do understand it would suck to be stuck there while you thought you were going to have a good vacation so that's very unfortunate, but I think trying to stay positive would help your stress also.
You can still be thankful if you're coronavirus free. You can still look forward to the day when you'll get out of that cruise. You can still be thankful you're alive. You've learned your lesson, so you'll plan better accordingly next time. But more than anything, when you're stuck at where you literally can't really do anything, you can spend time with the LORD. Reading scriptures, praying, etc. Jonah from the Bible would be kind of a similar example. But it wouldn't make any sense if you don't believe in Jesus.