I am so sorry that you are not feeling well. It is never fun to get sick, but while on vacation after you have planned and looked forward to it, is really lousy. My DH got sick a few years ago on the last full day of our trip with the worst stomach bug that he had in years. He couldn't leave the room, so I took the kids into the MK without him. It wasn't the same without the whole family together.
I always stress before we leave on our trips, making sure we have all had the flu shot and staying clear of sick extended family friends and friends. I run around in the trip with antibacterial soap to try to protect us rom germs while on the trip. But the reality is that when you are around so many people every day, you unfortunately get exposed to things and there may be nothing you can do to prevent illness.
I hope you feel better today and enjoy the rest of your vacation with your family.