Okay so im getting my 3 1/2 month old kitten spayed tomorrow and im an absolute reck..?

im affraid shes gonna hate me because i made her have a surgery and be in pain!!! ahhh. But also i was just wondering is their anything i need to do tonight?before the surgery? and also any suggestions about when i bring her home from getting spayed tomorrow for a fast recovery...I JUST CANT STAND TO SEE HER IN PAIN!!!