I don't really walk mine in the hot weather either; Especially because he loves to pull and pull on the leash for the whole walk so even after like ten minutes he's panting like crazy...and this isn't even in the hot weather. I do sometimes walk him in the hot weather but usually just a ten minute walk or so. I also go to school all day and my parents are working so he's left alone then for a few hours but he probably just sleeps through most of it. Remember that most dogs enjoy lying down and relaxing if they've gotten a walk or played with.

Don't be stressed...Just chill