Newborn suddenly stopped taking right boob

My newborn is 5 weeks old and we mainly do nursing while laying down.
Since 2 days ago, she is having nose congestion and I’m using saline spray a couple times a day.
She will scream each time I lay her down so I’ve been switching to nursing her while cradling her in my arms sort of half standing. It works until lunch time today and suddenly she doesn’t want right boob anymore.
So I’ve been nursing her on left boob only.
Any advice with congestion nose and making her take right boob?