Agree that the temp was probably off. Rectal temps are the best but obviously a lot harder to get in a wide open medical tent.
I would have like to have known what your pre and post race weights were. If your weight stayed the same or went up you could have been hyponatremic (low salt) because you took in too much plain water. If you lost a lot of weight (more than 5% of your pre race weight) you could have been salt and volume depleted simply because you did not take in enough during the race. To prevent this from happening in the future you need to differentiate between the two as the prevention strategies are very different.