Heya, long-time (nearly 20yrs) vegan here. =)
If your energy levels are low, then it has to do with energy, not protein. (Protein is a very poor source of energy for the body, esp. for endurance athletes.)
Make sure you're getting enough calories, and that they're mostly from carbohydrates. For a few days, actually count how many calories you're getting, and make sure it's enough to cover what you're doing (basal metabolic rate, plus training, usually 5-600 calories per hour for most of us).
If you're eating a fairly varied diet, protein is not going to be an issue. We really only need small amounts (World Health Org, ADA and other actual HEALTH organizations say between 0.4-0.8g/kg.) If you're eating enough calories, and it's not all crap like potato chips and soda, you're going to get more than enough protein.
Iron is more of a concern for people who consume dairy, since the calcium in dairy inhibits iron absorption, and also dairy contains almost no iron. (Many plant foods have iron, not huge amounts, but it adds up. Low iron levels will result in fatigue, although you won't 'feel' that it's iron.)
Christine is a great example, and she'll tell you the same thing about protein. Another good resource is the Sports Nutrition Guide put out by OrganicAthlete:
It's a free PDF download, although you need to sign-up, but that's free too.
There are other nutrition books too, i highly recommend Becoming Vegan by Vesanto Melina and Brenda Davis, it's a wealth of nutritional info.