Hi Lindsay, I'm sorry you've been having such an awful time. I'm glad your GP was understanding and has given you some help. Don't be afraid of the zoloft - give it a chance to do its thing, and you should be able to hang in there until Monday.
But please Lindsay, I am saying this again and I can't emphasise enough how important this is - please, please stop reading up about CC. Stop googling it, stop reading about it. It is NOT helping you, it is feeding your obsessive thoughts which is making you more and more anxious.
Take deep breaths (breathing out for longer than you breathe in), go for a brisk walk, marathon a new show or a movie, read a comfort book, do something, anything to distract yourself. As another poster said above, it's out of your hands - you've booked the test, you've got blood results on the way, and you've done what you had to do. In the meantime, think of it as your job to think about your situation as little as possible. We irrationally believe that thinking obsessively about things gives us some control over the situation, but it doesn't, it'll only eat you up and make you unable to function.
If you really feel you can't eat anything solid, buy some yoghurt and honey and eat that in the meantime. You can do this, hon, we're all behind you.