I feel your struggle! I have a Boston Terrier who doesn't handle heat well, the breed is known for it. When I got her - we would go on walks and she would refuse to drink water afterward. She would throw up too. Now I've gotten better at reading the signs but it's difficult! Since she won't drink when she's panting I will splash water on her body. We have a cooling mat, cot, and bowl that someone gifted us. I've heard of cooling harnesses too. Maybe staying off hot surfaces during a walk, going on grass instead? My guesses are as good as yours though...!