Help! Possibly mastitis?

Sa

I’m 3.5 months pp. I frequently get plugged ducts. At least I used to until I stopped drinking milk. I still get them if I don’t empty my breast fully either with baby or pumping.

But from two days ago I noticed this round lump in my breast, that doesn’t hurt and doesn’t feel like a plugged duct. It feels like a painless knot. But it has not gone away. Today the skin got red on top of it (round shape), but maybe it was from me pressing on it a lot when pumping. It gets a bit smaller after I pump or breastfeed.

Today the entire breast is in pain. I have got this before and it went away in a couple of days, I attributed to being delayed in pumping last time (and my breast got hurt I guess?!).

I called my local LC center and they probably will call me back tomorrow at noon, I was wondering if anyone here can give me some opinions before then? Does this sound like mastitis? And if yes, is there anything I can do to stop the progress?

Ps I don’t have a fever, but I feel sick somehow, like very tired ... but it could be from waking up multiple times last night also ...