Had my bitch for a gallop last night. She started to yelp and fell down. She rolled yelping for about 15 seconds. She got up and fell down.again i reached down to her to try and settle her down. She snapped me. Then a few seconds later she was fine. Took her to the vet and he said that she probably cramped. Normally She wouldn't harm a fly. Has anybody had much experience with this problem? Is it rare for the dog to try and snap while cramping?