In total shock. None of us truly believes we will get the big "C". I know my head spun for weeks, and even 4 years later, after multiple surgeries, chemos, complications, I am still in disbelief.
You've just been hit with a life-altering (life-threatening) piece of information. It takes time to digest it. People commonly feel numb, out of control, panicked, calm, in dis-belief. As DaveWaz says, there is no right or wrong way to feel. Your mind and body have you on this one, and whatever you feel is right for you. However, don't hesitate to look for support, for a counselor to help sort out the myriad of feelings.