My four-year-old Blue Heeler /pitbull mix is suddenly drooling excessively. She is generally healthy, although lately she’s showing signs of a potential allergy to a food that I switched her to, based on gum swelling (happened with my other dog). She went for a 4-mile run today. She is not acting anxious or licking, she’s not whining or showing signs of lethargy. However, she is leaking like a faucet out of both sides of her mouth. Is there something that I should monitor or take her to a vet?