Cluster feeding?

First time mommy, EBF 6 week old. 

My little girl has taken to a weird feeding schedule. I can guarantee to be with her for at least an hour per feed just recently as she nurses (approx. 7-10min) is awake and content and then 30-40 mins after wants to nurse again. Usually nurses twice (sometimes a 3rd, again 30-40min after) and then is content and goes to sleep in 3-4 hours stretches with a wake period of about 2-3 hours mid afternoon. Normal? Could this be her version of cluster feeding? Growth spurt? Just would like some insight :)