After 13 years of living with this I strongly advise you to make sure and be kind to yourself. There are no prizes for martyrdom in this race and nobody thanks you for it. Working is great if your body can cope but with 3 children who need all the love and attention it's great for them for you step back and smell the roses with them. I worked through my first series of chemo and radio but I was a lot younger and fitter but it WAS hard at times but other times good to be a normal person again. It's quite a dilemma isn't it really.
Your experience with your professor warns us all about being vigilant about our health professionals. Take your cruise, take in big breaths of sea air and enjoy it with no looking back and feeling guilty or any negative feelings.