Your iterations are too short!

Microscope

The trend towards shorter iterations, while being a good demonstrator of increasing development capability, also tends to rob planners of an opportunity to step back from project minutiae. 1 month or even 3 month “iterations” can augment the phase (release) planning process. 1 week iterations give much less scope for that. If you want to run 1 or 2 week iterations, make sure you have a sound phase planning process operating around it.