Swollen, sore mass: Urgent Care or wait until Tuesday?

History: I am 48, still get periods, breastfed two children who are now 9 and 14. In 2003, I had a lump in my right breast. Mammogram, ultrasound, needle biopsy determined it was fibroadenoma. Whew! Had surgery to remove it. Zero issues with either breast since. Until a few days ago. I came down with a random, sudden low-grade fever. Chills, a bit of fatigue, but nothing too awful. I couldn't figure out what it was, but it went away the next day. A few hours later i notice my right breast is tender. I don't think twice about it because my period is due, and boobs are weird. Then, that evening, the fever comes back. It's still low, but at 100.8 it's higher than it was the night before. My breast is considerably more tender, and sore to the touch. It's the right side of my right breast, the same area where I had the fibroadenoma removed.

I keep thinking it's just period related, and assume it will go away in time. I feel for a lump and all I can feel is a thick, dense mass with no discernible borders. Now I am slightly alarmed. It feels like mastitis and clogged milk ducts, that's the closest way I can think to describe it. But I haven't breastfed my "baby" in over six years (she nursed until she was about 3.5 years old). When I got in the shower last night, I was shocked to see that the sore area is indeed red and inflamed. In the mirror, I can see that the redness wraps around most of the right side of my right breast. Now I'm freaking the f out. My fever is gone, which is a slight relief. However, I can't get past the fear that I might have inflammatory breast cancer. I should add that I cannot stay away from Dr. Google and I also have a tendency to assume the worst immediately.

I obviously know I need to see a doctor soon, but I'm assuming I will need diagnostic imaging and likely a biopsy. I am a single mom to two daughters, and I have sole physical custody. We have lost six close family members in the past five years, four to cancer. My mom was one of them, and she beat colorectal cancer in 2007 but succumbed to a short, awful battle with uterine cancer in 2016. No family history of breast cancer. My kids are emotionally fragile due to all the loss and trauma they've endured and I do NOT want to freak them out by suddenly dragging them to urgent care on a holiday weekend.

I'm scared and anxious but I'm holding it together fine, probably because I have had so much practice over the past few years. Am I being foolish by deciding to wait until Tuesday to see a doctor? Would urgent care even be able to do anything?
Thank you so much for reading. This is my first post here and I was so relieved to find this forum.

Edit: I seriously doubt it's relevant, but since lymphatic vessels can be a factor in IBC, I wanted to add that I was diagnosed with secondary lymphedema in June 2017. I've never had cancer before so I don't know how/why I developed it. I had two c-sections, 2004 and 2009, and a hypertensive brain bleed in 2015 (fortunately did not need surgery for that, just 8 days in CCU/ICU combined).