Concerns on long-term health

Hello. I've been eating a plant-based diet for over three years now. I hear stories of individuals struggling with autoimmune issues due to B12 and iron deficiency. I have experienced some symptoms of this--low heme-iron, fatigue, dizziness, shortness of breath, and fast heart rate. Sometimes I do get winded from jogging. However, I think this is more related to a lack of calories and consistent eating. I have a history of restricted eating (meaning amounts) and try to make sure I eat throughout the day. That usually fixes it. I also take a B12, Vitamin D, and Omega-3 multi to prevent this and eat fortified foods. My diet primarily consists of whole plant-based foods with minimal oil. I have checked my ferritin and I believe it was fine, but this is something I do worry about.