I like to eat a Specail K protein meal bar two hours before a run or race.  It's light, tasty (like a rice crispie treat), and has never caused me any woes on a run.   I add a half a scoop of Gatorade to my water bottle, and at mile 8 consume one Gel - mandarin orange is my favorite. 

Hope that helps!

For three miles you shouldn't be running out of fuel unless you were fasting for the entire day before.  Any chance you are simply running too fast for your current condition and you are  tired?

Gatorade will be just fine. So would plain water.    For three miles your burning anout 300 calories - not what one  would consider a major caloric drain.   As for C-milk it's a great recovery drink but after a lot more than three miles. You may be ingesting more calories  then you expended in the run.    I would be careful about mile products before a run or at least experiment.

Eating something small before your run is usually good - a banana is perfect. 

Also load up on certain foods, such as arugula/beets/leafy greens, the night before your run because these foods can boost your nitric oxide levels.  Nitric oxide vasodilates your blood vessles so more oxygen can get to your muscles, therefore, you can have longer, faster workouts.  You actually regulate your levels in your saliva! I use Berkeley Test Nitric Oxide test strips, they really help me monitor my nitric oxide levels throughout the day.

Dont neglect your healthy protein, carbohydrates, and fats found in other foods either!