A week of symptoms with changes??

Hello to all and I cannot believe I am posting on a cancer forum, but, here I am. I hope all is okay and the diagnosis is correct and not IBC. Just looking for input at this point. Last Sunday I noticed a quarter sized red place on my left breast. I probably would not have noticed it but it was VERY painful, like a boil maybe. I shrugged it off. Monday evening, it was the size of a tangerine, raised and hot as hell and my breast was obviously larger.THERE IS A DISTINCT LUMP IN THERE. Tuesday after work, it was much larger, still fevered and painful with itching and I could actually feel something happining within. I know that sounds weird, but I can still feel it randomly. Went to the ER and they sent me home with antibiotic scripts and a diagnosis of cellilitis. The next morning, I got an appt. with my Ob/gyn. I saw her NP and as soon as she looked and attempted to feel my hot tamale, she went immediately to fetch my Dr, I was then told it is......Mastitis. I am very leary and paranoid. I have done a months worth of research and feel I may have been misdiagnosed. I am taking the antibciotics, and the fever is about gone, the redness has changed color  from the reddish brown to a more "bruised" appearance. Size of the reddened area is still about the size of  an orange. Can still feel the lump. I still have shooting random pain from the top of the breast to my nipple. I have noticed that I am exteremely drained and need to rest or nap by 2 in the afternoon. I have not had a temperature through all this. I will go Tuesday to the breast center for tests, on my own as my Gyn wants me to wait until the 5th to see her and then decide what to do. Am I outta line? Anyones' symptoms like this, especially the color change??? Thanks to all and hoping for the best.