+1 on what everyone else said. If none of you completed your planned workout, that tells you a lot.

I'm not sure what your weather's been, but here, it's been so variable that no one has been able to acclimate to heat. If it stays hot between now and your race day you should be fine. If you don't get a chance to consistently work out in those temperatures though, that's when you just can't acclimate.

Good for you for knowing when to say when, and not trying to push past your limits. As the saying goes, any workout that you can walk away from is a good one...