Need some help

I’m in need of some help. I have a 3 month old baby boy who seems to get over heated so easily! He gets lethargic every time we are in the car and it’s hot.. we also live in Florida. It happened when he was a little younger but as it’s getting hotter it seems to be happening more. We cool the car down and keep him in cool clothes. But we are so scared to put him in the car or go anywhere. I’m going to make an appt but just looking for advice or if someone has experienced this??