You will be fine. Several years ago, I did a short camino from Sarria to SDC as part of a longer trip visiting family, and got distracted talking to fellow pilgrims at the hotel where I was staying in Sarria. I actually forgot to get a sello from that hotel clerk and walked out and passed the railroad tracks at the edge of town and went up the hill before I released that I did not have a sello from Sarria. Fortunately, there was someone at Barbadelo stamping credentials and because there was more than 100 km left to get to SDC, it was deemed to be OK by the staff at the pilgrim's office. You'll be fine!