Suggest Treatment For Enlarged Tonsils

13 year old very active and fit daughter has large swollen tonsils with brownish mucus spots on them. No white spots, no fever, some vomiting at night of mainly the liquid she drank and some phlem. Very sore, weak, achy body. Not eating much at all, drinking a little. Leg pains and upset stomach pains. This is the third day she has had this. Does she need an antibiotic?