Martin, take breaks whether or not you feel you need them to prevent injuries in the long run. It's nice to take off your shoes and socks and wiggle your toes every 2 or 3 hours, like Sil says. And in the evenings, look for the basins that some alburgues have, and give those tootsies a cold soak! It'll do wonders!
Also, please don't feel that you must complete each 'stage' as it is written in the guidebooks!
There are many "in between" places to stay, and often, by staying "in between" stages, you are able to stay in places with fewer pilgrims.
Last night, we looked through our notes from our last Camino. We found we walked between 6 to 8 hours per day. There were a few days we only walked 4 hours, maybe because we wanted to do some "touristing" in that place.
One time I caught the flu and we stayed in a private hostal for 3 days while I recovered so as not to pass along my flu to other pilgrims via crowded refugios.
Just go at your own pace... no need to plan too exactly.
Let the Camino carry you along... you'll be fine.