Hi RobT
Dont worry about it all too much, I was in and will be in the same position. I have been to uni and had a million and one differrent part time jobs while there which i need references for again. I did struggle but managed to get it all sorted.
As said earlier on make sure you have someone (family friend etc) to be your reference for any employment gaps. They just have to say they know where you were when not employed. Think you need these references if the gap has been more than 5 days. (not 100% sure on that)
Best thing to do is write down all your places of work and dates of joining and leaving on a piece of paper and put down what employment gaps there are and why. It just makes it all easier for you for when your filling out the form on thurs.
But try to relax about it all. Im in the exact same position as you.
Is your medical on thurs?