Oh boy, i just went through this in feb and march. yup it sucks but I agree with Tumblequeensmom
. Make sure you STAY OFF OF IT. Use those crutches for as long as you need to, and like eeyoretumbles
said, do RICE. The three main things to remember is to rest it as much as possible, Ice it lots...especially after school, and Elevate it!
It will heal faster if you stay off of it as much as possible at first. If you try walking on it and using it too soon it will just make things worse, so be patient.
Make sure you don't do any rehabilition exercises until the swelling, bruising, and pain go down and make sure you get the go ahead from the doctor first! That is really important cause you definitely don't want to injure it any more than it already is.
Good luck, be positive, and just try to enjoy your time off.
Oh and when you do get back to the gym make sure you tape your ankle to train (this might be obvious). I taped my ankle for the next few months, until the end of my season in the beginning of May, to prevent further sprains...which is common after a sprain.