Yea, I had the same thing happen to me, and had to take antibitiocs for mastitis in the end. The mastitis came back twice so I feel for you. If you can meet with a lactation consultant, do it. They will have ideas. If your fever goes over 100, you should call your doctor. In the mean time, take lots raw garlic to fight the infection (helped me not have to take an extra round of abx), ibuprofen for the pain and swelling, and get some probitiocs because if you start abx for mastitis, you'll want to do everything you can to keep your good bacteria. My babe did not love being on the abx with me. She got diarrhea.
Nurse in every position you can imagine. Football hold, babe sort of laying on you vertical, lay him down on the bed and hang over to nurse him or on all fours. The all fours one is especially good to use gravity to help move things along. Massage the affected area while he feeds. Massage it in a hot shower. Put hot compresses on for 15 minutes before feeding or pumping. If he only feeds a few minutes and is not emptying the breast, pump after he eats. It will hurt. You have to nurse through it or it will only get worse. The ibuprofen will help.
The abx I took (Dicloxicill) wasn't totally effective at eliminating the infection for me. Later after I saw the lactation consultant she said if it happens again to request a milk culture from my doctor, because they can identify the bacteria and choose the best antibioitic that way.
Oh, and everyone told me rest was the biggest thing I should get to fight off mastitis. Um, yea, I have a baby who likes to feed every two hours or less. Telling a new mom to rest is kind of ridiculous, but do try to get as much as you can. If you are able to pump, have someone give the baby a bottle if possible and go to bed. Or at least have someone help out to the max for a day or two to get your rest.
But do contact your doctor if the fever persists. I ended up in bed with the chills and flu like symptoms until I started abx. Good luck!