i fractured my hand two nights ago and its impossible for me to write with the cast on. I am wondering what i should do. I know i can defer exams but is it possible to defer all my exams? And if it is, where do i start the process?

Contact student accessibility services ASAP. This is not a reason to defer your exams; you would just need accommodations (for example, typing your exams, or having a scribe + extra time since this takes longer than writing yourself). They usually want more notice but obviously you couldn't foresee breaking your hand. They should be able to work something out for you.