Hi Angie. Just wanted to tell you there are lots of vegetarian runners on the WISH boards. If you have specific questions or just want some feedback post a question about it on the events board and I bet you will get some responses.
I am a 99.9 percent vegetarian. I will very rarely have a hot dog--I know how yucky, but I like hot dogs. And that's about it. I run 3 times a week and have completed 2 half marathons last year and 2 this year so far. My dh is mostly vegetarian--he eats chicken/fish when we go out and will share a hot dog with me on occasion.
Anyhow, I have not found it hard at all to get what I need nutritionally. Great sources of protein: greek yogurt, eggs, beans, cheese, nuts. I try to eat protein after a workout--even if it's just a string cheese or a spoon of peanut butter. Sparkpeople will let you track your food and estimates how much of which nutrients you are getting and what you are low on.
I do take a multi-vitamin--without iron. So far I have been doing ok getting iron from veggie sources.
I think what makes working on weight loss/ being a vegetarian/ and an athlete a little challenging is realizing that some of the good sources of protein may be a little higher in calories--nuts, eggs, beans, cheese, etc. but you just have to modify how you eat them. Have your pb on celery or by the spoon instead of on bread. Substiture a plain hardboiled egg for chicken or lunch meat. Eggs are pretty low in calories. And realize that if you are getting your fat from nuts, you probably need to avoid butter, sour cream, etc.
Anyhow, I hope some of this makes sense. It's very doable. Just takes a little thought.
Good luck with your running!