Im just not sure i believe diagnosis

Hi, I am a 28 and in mid december i found a lump in my right breast at the 2 oclock position that was fairly big but not too uncomfortable. I was worried but hopeful the it was nothing as it seemed to hurt with my period making me believe it was a benign fibroadenoma so i waited until after the holidays and made an appointment with my obgyn. She felt the lump and agreed it was probably nothing to worry about and sent me to have imaging done. During the imaging they noted that it was a bi rads4 and needed to be biopsied. I was worried but still hopeful. After the biopsy my breast swelled like normal and after about 4 days the swelling went down but on day 5 i woke up with my breast swollen again. I assumed maybe it was just some fluctuations in the healing process so i gave it a few more days and in the meantime my results came back negative for malignancy and infections but at 2 weeks post biopsy the lump seemed to be growing towards the biopsy site that was roughly at the 7 oclock position on the opposite side of my breast. I finally talked to my doctor and she said to call if it started to get red or oozing so i waited it out but 2 days later my breast was completely red and the lump had gone form a small quarter sized lump to almost my entire breast. I called and they scheduled me for an emergency appintment with an NP and she looked at it and prescribed antibiotics as it seemed infected. I was hopeful that the swelling was just an infection and would subside with antibiotics. After a few days on antibiotics the swelling and redness seemed to he getting better but after 3 days on antibiotics the redness and swelling returned. I waited a few more days and in the meantime they called to schedule an appointment with a breast surgen in 3 weeks to have it removed as they still had no idea what the lump was. It wasnt cancer, an infection or a fibroadenoma. It needed to be removed for further testing just to double check. Well a week after the antibiotics were prescribed i went back to my doctor as the lump covered my entire breast and was still bright red all over. My obgyn looked at it and decided it couldnt wait 3 weeks to be seen by the surgeon so they fit me in the next day for an emergency consultation. At this point i was convinced i had some kind of missed cancer or an agressive benign tumor and worried i was going to lose my entire breast. I finally get seen by the surgeon, she took a short look and then did an ultrasound for about 2 minuets and told me i have something called glandular mastitis which is a rare autoimmune disease that has only had hundreds of cases worldwide since 1972. The treatment is steroids and immunosuppressive medications but she wanted to take time and look over my biopsy and imaging to double check before putting me on life altering medications. That appointment was on thursday and she will tell me what is decided on tuesday but in the meantime the “lump” that is supposidly just extream inflimation caused by my own body is continuing to get bigger and bigger every day i have to wait and im just not sure it isnt inflammatory breast cancer. They told me because of my age and how it started with a lump it would be rear for me to have IBC but this autoimmune disease is an even rearer chance. I am just so overwhelmed by this whole process and in so much pain from the swelling that i dont know what to do. I dont want it to be cancer but i just cant convince myself that i somehow am 1 of only hundreds of people to have this disease. The odds just dont make sense. I have a 0.37% chance of having glandular mastitis but have a 12% chance of having breast cancer. It just does not add up to me. Even if it isnt cancer either i just cant convince myself to feel relieved by this either.