If I’m getting sick with a bad cold and need to stay hydrated and take lots of vitamins throughout the day to get rid of the impending sickness quickly, should I break my fast [and take the vitamins] or fast knowing I’ll get even more sick which will cause me to break my fast for more days later on?
If you are ill [currently] and unable to fast because you need to take medicine during the day you can break your fast and make it up after the month of Ramadan. However, anticipating/assuming that you will get sicker later on because of fasting is not a valid reason not to fast if you are able to do so at that moment.