You miss the cruise ! short n sweet i think you mean do you get your money back ? well depends what type of insurance you have taken out check the small print ,thats hoping you have got insurance .
You claim on your insurance.
It would be a good idea to go to your GP rather than spend an arm and a leg visiting the ship's doctor at £20 a consultation.
It would be sensible to look at the cancellation provisions on the cruise terms and conditions if there is a risk you can't go on the trip.