Apple I feel for you. With dd1, I came down with symptoms very suddenly the weekend before my 6 week postpartum exam. I was at my parents house feeling fine, then suddenly I had a fever, chills, an achy boob, and a generally miserable feeling. I nursed often, used a heating pad, massaged I think, and treated the fever with meds, and I got lucky...symptoms went away on their own. When I saw my ob, I told her about it, and she could still see the red streak on my breast. She said let her know if I had any more trouble, but I was lucky and everything stayed fine. (To anyone else though, I would not recommend waiting it out, it just happened to be off hours when this happened and I knew I'd be seeing my Dr soon.)
I did have a plugged duct a few months later. Just one section of boob became engorged and I thought I'd never get it to drain. It was so sore. I tried all kinds of things like you can read online. What finally worked for me though was using a heating pad right before she ate and then nursing like so: put baby on her back on the floor. Hover over baby to feed her (I guess for gravity to help) with her chin lined up with the blockage. I'm not sure how well it'd work with a newborn because mine was bigger at that point. She was also sleeping through the night, so I did that first thing in the morning when she was hungry and likely suck really strongly. I felt like having her chin over the blockage was the biggest help though. There was a stinging sensation as she relieved the plug, and it remained achy after for a while, but finally it was softer instead of rock hard in that section!
I hope you're feeling 100% soon! Or as close as possible when you have a newborn!