Sorry for the boob picture!!

I’m a first time mom, my daughter is a month old. Just today I noticed I had a light red patch under my nipple. That breast is tender to the touch but there’s no lumps of any kind. I feel totally fine, just my boob hurts. I know women say mastitis feels like the flu, but I wonder if this could be the start of it or if it’s just a clogged duct.

Any idea? I have my 6 week check up on Friday but don’t really want to sit around waiting for it to get worse!

(I’ve been nursing her all day)