Ok, I'm not going to get into gory details but several family members have worked as EMT's or in the medical field, and the extraordinary things they see from everyday "ordinary" people are amazing. It is amazing how much sheer will power can get you through.
Now that being said, any single of Sakura's feathers was a HUGE deal. One was considered the strongest power source of the world (piffle world), another was able to grant any wish and temporarily raised multiple dead people, and one protected an entire building and water source from corruption. Sakura has retrieved how many now?
Think about the sheer amount of power this girl has within her at this point! She may not be full strength yet, but her power probably rivals Fye's. We haven't seen what this power can really do in her hands yet, but self preservation is strong and often instinctual. So I wouldn't doubt that those considerable magical powers of hers are helping keep her alive and aware.