What I meant is, it sounds like you have at least a slight case of anemia, which is more common in those who eat meat (it's about a 100:2 ratio for those who do and don't). Anemia just means 'lack of blood', and is most often caused by lack of iron, but can also be caused by lack of b12 or folic acid. It's more often due to not absorbing the nutrients than not taking them in. The best advice would be to take vitamin C in the same meal that you eat vegetable based iron to increase the absorption. Those who eat meat often don't get enough vitamin C, which may be part of why they become anemic more often. I'm not turning this into a debate about the health of meat eaters and non, not interested in that, just saying that it could be due to a lack of vitamin C during meals, which helps the iron to be properly absorbed, and is often lacking in a meat based diet.
Edit: Iron supplements should only be taken at the directions of a doctor, it is best to take it from natural (i.e. vegetable, legume, grain, nut) sources.