mastitis or something else??

So originally I thought I had thrush or a yeast infection in my nipples. They are swollen, very bright pink, and I get a horrible burning/tingling feeling even between feeds. My breasts have also felt very engorged even though I'm pumping and feeding constantly. Well today I woke up with chills, aches and a fever of 101. My doc prescribed me antibiotics but not I'm afraid those will give me thrush or worsen it if I do have it ugh. Could it still be mastitis even without streaky red breasts or a noticeable red lump that they tell you to look for?