Swelling and lump, panicking :/

hi everybody, I posted a few days ago but now that I have an ultrasound on the way, I'm developing some new symptoms that are scaring me even further.

What started as a red rash is now a bruise that is fading. But now there is a lump in my breast under the bruise. It's hard and small and painless, and it doesn't move.

On top of that, the last few days my breast and armpit have swollen, enough that my doctor noticed it, and my armpit is sore.

I'm just running out of reasonable explanations and was wondering if anyone had ever dealt with this and had it turn out to be nothing?

Sorry for the ramble, panic will do that to you!