well, it takes time to get in shape. If you don't have a couple three months there are things that can help deal with heat.
start drinking water every day, especially the day before and ALL day at the track. Every session, down a pint or so.
Stay in the shade
Pour some water down the legs, arms, back/front of your leathers. "poor man's ac". Soak your head with water before/after.
Go FAST on the track, seems to make the water feel cooler.
Soak a hand towel with cold water and wear it around your neck.. all day.. when not on the bike.
Couple advil in the morning.. couple advil at the end of the day (maybe that is just me being 42..)
Wear sunglasses, less fatigue on the eyes.
Wear earplugs.. (see above but substitue "ears" for "eyes")
Don't drink a bunch of beer the night before, alcohol dehydrates you.
EAT meals, don't skip em.. i can't eat much during the heat of a day but at least a couple bananas and powerbars.