Hmmm, I'd probably go to the doc and get her checked out - make sure it isn't a blockage or twisted bowel. It does sound kind of strange.

Otherwise dietwise, the only thing I was ever told to avoid when DS had an upset tummy was dairy as the enzyme in that is the hardest for them to process. I had to go off it for 2 weeks.

But really, I'd get it checked out medically first. Especially as she is so young. BF babies can go for ages without poo - my DS used to go for 7 days, we had what was known as 'Poo Sunday'!! But that didn't start until he was a bit older than your DD.