I'm not sure what radical changes you made to your diet but meat is not really required and heme iron has some other detrimental effects. I can't argue with your specific case but if you are interested in trying again here are some resources.

Vegan society recommendation: Good plant sources of iron include lentils, chickpeas, beans, tofu, cashew nuts, chia seeds, ground linseed, hemp seeds, pumpkin seeds, kale, dried apricots and figs, raisins, quinoa and fortified breakfast cereal.

Another good article.

A pro tip is to add citrus or a vitamin c source to your meal to help with absorption and avoid caffeine around the meal which can decrease absorption.