my thighs,arm and legs hve bcome weak and has gt told me to do anti nuclear antigen test? please help?

hello doctor,

After my second child cesearian i have been experiencing swollen feet,swollen thigh as if its filled with water and swallen arms…my joints aches alot and feet and knees have become sensitive and weak…i am 25years old…please help…my doctor said i should do anti nuclear antigen test???