LO doesn't like one side

My DD (5.5 months) always preferred the left breast, but overall never had a problem using both breasts. Now suddenly today she wants nothing to do with my right! She will pull her head back, and actually try to push away from my breast and starts to cry. Like she reeeaaallllyyy doesn't want it. At first I thought maybe she's just not hungry, But then I switched to the left and she's all gimme gimme gimme! 😨 At the end of the day I just want her to be fully and happy, but I'm worried about my right breast's supply. I started to pump but it's just not as efficient as baby eating from it directly. I think she's starting her teething phase too. Could that possibly be the culprit (have no idea how but...maybe?)?