You're not alone. DH and I lose our appetite in the heat. And DH's stomach is messed up anyway with his hunger signals (he'll go from not hungry don't talk about food to STARVING and throwing a tantrum in the blink of an eye), and when his blood sugar goes low it's not fun for anyone. WDW makes it easier b/c we generally have a TS each day already planned so food is on my mind (or, rather, getting to the reservation). At
Disneyland it's harder because I rarely have a TS planned and it's easier to go, oh, 9 hours without remembering to eat. (true story) (figured it out when the 5 and 37 year old guys in my family were having a huge and ridiculous argument in Tomorrowland, and it suddenly dawned on me that no one had eaten since lunch and it was full-on nighttime)
Now now, you should never have been sprinting. No running; just walking with purpose! We haven't slowed down any since FP+. I am not a saunterer by nature!
Yikes. Eat if you're hungry, dive.