Allergic to to something in my milk?

My 7 week old has had a rash for 2 weeks. We went to her pediatrician when it first popped up and she told us that she had a virus and that it should go away within 10 days or so. She still has a rash but it’s not all over her body like it was. She has acid reflux and has spit up so much in the past 48 hours. She also has diarrhea and mucous in her stool. About 1 hour after giving her breast milk from a bottle her face started breaking out and getting red again. Then about 1.5 hours after her rash flared up it started going down. I’m wondering if she is allergic to something in my breast milk. Is that possible? She hasn’t run fever. We scheduled an appointment for later today and are going to see her pediatrician. Just trying to see if anyone else has has problems like this or similar to this? (Pictures of rash below)

Once it started clearing up. —