From what I remember my kids all went through a growth spurt at around 3 weeks, then another at 6 weeks. Probably why she wants so much.

Plus the comfort as well. She's probably not sucking all the time coz she's not hungry all the time. You are a dummy as well, so its probably all about comfort

Things sound so much better & less stressful for you now! & don't worry, the left one will catch up once she's back on it too.