I think based on his discomfort level that it might be best to take him to the Vet. Are his gums nice and pink? When you feel him is there any areas that seem uncomfortable or painful to him? I'd keep the Gas x strips going just to be on the safe side. Can you put a fan on him to see if that helps cool him off?
_________________________
Rosa

Proud Mom to Eli and Kodiak
and never to be forgotten, Shiloh and Shoshi
Every dog deserves to have a human that thinks its the greatest dog that ever lived!