Honestly, for the amount of running you're doing, it sounds like you are NOT eating enough, plain and simple. I'm a runner too, and the meals as you've described are just not enough to sustain the level of activity you're doing--that's a LOT of mileage for very, very few calories.
Your body most likely thinks it's in starvation mode and won't let you lose any weight, since it's trying desperately to hang onto what few calories you're consuming. Seriously. That really sounds like your issue.