Thanks for the query.
If you are breast feeding your baby, better to use progesterone
Because the estrogen content in the combined pills like althea can compromise the breast feeding.
Your symptoms may not be due to the pill.
Better to rule out the possibility of any pelvic infection
, urinary infection, mastitis once.
Because these can present with high fever
with chills etc.
Consult your doctor undergo examination and if needed change the pill.