hi, I read your post, sorry to reply this, but have you checked if you have worms? one detail how you recognise it, is if you have is if 'your bottom' is itching at night. Sorry for all those details, but it is a quite taboo thing to talk about, but happens quite often ;-)
Have you ever seen a Gastroenterologist? I believe you have some type of gastro condition/disease causing the anemia. My guess, possible Crohn's Disease.
It sounds like it might be IBS, irritable bowel syndrome. Have you ever been tested for that? You may also want to ask your Dr about being lactose and gluten intolerant. Take care. Remar