I understand not eating breakfast, and being physical in hot weather ...,. I commuted and worked labor jobs in Central Florida for a long while.
As others have said, drink before you are thirsty---just do a little bit steadily.
Same with food (I had a really hard time eating a big meal and riding and working and the heat made it a hundred times worse.) Just as with water, I would suggest trying eating small amounts frequently---I used Powerbars, peanut butter sandwiches, fruit, dried fruit .... experiment with what works for you.
For me., particularly as I have aged, I need to really watch peak efforts. Going into the red should be avoided ... you can build up too much heat for your body to radiate away.
Another thing which worked for me was not getting chilly at home. I wouldn't recommend running the air too cool .... get your body used to being warm all the time, so the heat of the day isn't too big a change (tough if you have a partner or family.)
The biggest thing is too take dehydration/heat stroke seriously, and always keep water and sports drinks flowing through your system, and watch your maximum efforts.