Tan I had same happen with Jake when he was little. As long as their poos aren't pebbley and their nappies are still wet they aren't constipated. My Dr told me a BF baby can go up to 2 weeks without pooing - but would hate to see it when they did

Try bicycling her legs, or pushing them both up to her tummy when she is lying on her back - kind of like leg lift crunches. This helps move wind and might get her bowels more active, and try massaging her tummy in a circular motion where the down stroke goes down her left side - this is where the bit that leads out to the colon is (not good on anatomy!) Google baby massage and most sites have a bit on this.

Good luck!