Pregnant while breastfeeding- symptom?


So i should be around 5 1/2 weeks pregnant, still breastfeeding my second. Last week i found a lump in one breast, near the nipple. It seems to have branched out, and 3 days ago got dislodged while LO was nursing and now part of it is under my nipple. It has grown to over half my areola, it kind of feels like a bunch of twigs, with 2 marble sized bits?

Anyone have any idea what this might be from? Maybe from nursing while pregnant/hormones? I have an appt set up just looking for ideas of what it could be.