I'm sure you've already heard this, but drink some water. Then drink some more. Then have another bottle of water just to be sure Dehydration totally sucks, and by the time you notice the symptoms in an environment like that, you're already probably pretty close to passing out. I just finished up a deployment to Kuwait, and averaged about 1 to 1-1/2 gallons of water a day. I'd pee maybe twice the whole day, everything else came out as sweat. Good times.....
I wouldn't call the camel spiders harmless, but they are non venomous at least. They are actually quite an aggressive predator, and will bite, er... pinch, actually. Those massive Fang/Jaw/Mandible things are actually pinchers, like a scorpion. During the daylight, they will follow you to try to stay out of the sun, in your shadow, giving the impression that they are chasing you....
Like everyone else has said, keep your head down, and get back in one non-bleeding piece. Even in supposedly "safe" areas in the rear, the poop can still hit the fan.
Mike