-Makeup (the main 3 things to have would be -concealer in case a pimple pops up suddenly, -lip gloss to add a little sparkle to your face, and -mascara to play up your eyes in case you have to pull an all nighter to study and your eyes too all baggy)
-Cellphone (just MAKE SURE the phone is turned off if you go to a school where they do not allow you to have cell phones during the school day. it might be a good idea to take the battery out so that there is no chance it will go off during school hours)
-Tampons/Pads (in case mother nature decides to pay a visit a little earlier than usual)
-Gym Clothes (if you need them)
-Pens, pencils, books, etc. (obviously anything you will need for school)
Also, I DEFINENTLY think you should have a backpack. I used my friend's tote for a day one time, and my arm almost fell off, it was so heavy! I got bumped in the hall way and my tote flew open and books went everywhere! Backpacks are easier to use and don't come open unless you unzip them. Also, since your back is stronger than one arm, your load won't feel as heavy.
And if you are creative and talented at stuff like that, you should go for it and decorate you backpack! Just make sure you have a backup in case your creation doesn't come out looking as good as you planned...good luck and have fun! Also, are you nervous about getting your HSPT scores back??? I am!!!! They come out on January 9th for me...good luck!