Leah, I'm sorry you're sick.
If it's a cold, it will have run its course by the time you leave in a week, since they typically lasts 7-10 days. That's good that you're taking vitamin C, D, and Zicam (Zinc).
For the sore throat, gargle with warm salt water and a capful of hydrogen peroxide. I always brush my teeth after gargling with that mixture, because I don't like the taste it leaves in my mouth. I recommend buying a new toothbrush, so you can throw the one away that you're using now once you feel better. You can also clean it after each use by rinsing it under really hot water and pouring some hydrogen peroxide over it.
Drink lots of water and hot tea with honey. Suck on throat lozenges. Take Tylenol for pain and fever. Eat chicken noodle soup. Get plenty of rest. (I know that's not easy with a young child, but he can go over to grandma's, if you need to take a nap during the day.) If you have congestion, take Dayquil (or some type of decongestant) during the day and at night.
I had a sore throat, fever, and congestion the week after Christmas (on my vacation, woo hoo!) and went through this a few weeks ago. Everything I mentioned helped me get over it in 5 days, just in time to get back to work.
Try not to worry... you'll be feeling so much better by the time you go on your cruise next week!
(((hugs))) Cece