If you cannot, at least express your milk as best you can in the meantime. Restart breastfeeding as soon as you are up to it, the sooner the better. Continuing breastfeeding helps mastitis to resolve more quickly. There is no danger for the baby. Rest helps fight off infection.
Fever helps fight off infection.
You will feel better and the amount that gets to the baby is insignificant. Amoxycillin, plain penicillin, and many other antibiotics often prescribed for mastitis are usually useless for mastitis. If you need an antibiotic, you need one which is effective against Staphylococcus aureus . The last two are effective for mothers allergic to penicillin. You can and should continue breastfeeding with all these medications.