Why is it at night I wake up freezing and soaked in sweat?

Night sweats. For a middle aged woman, this would likely be due to menopause. In people of other ages and for men, the common causes (but actually pretty rare) include occult infection (eg, TB or a subtle virus infection), certain kinds of cancer (leukemia, lymphoma mostly), and medications. The ssri antidepressants are famous for doing this, particularly paxil (paroxetine).