What Causes Shivering, Fever And Pain In Entire Body?

Hello dr . During my pregnancy I was having hypothyroidism. So I started taking medicine . Now its been 2 mnths since my delivery. I checked my thyroid it came 1.20 . Now I strtd suffring from severe shiverness and den gt fever n my whole body pain badly. I got my check up again n n TLC came 3700 n platelet count went 1.35