Can't eat

I've always had a problem with eating, specifically not eating enough. I don't know why, I just forget to eat and when I finally remember I just always feel queasy at the thought of eating and can actively feel my stomach rejecting the thought of food. Which is odd because I could not eat for two days and be in actual pain from how hungry I am, look at food, and just feel sick when I think about eating. And sometimes I force myself to eat but I end up with this feeling of guilt and shame that stays with me all day. I dont know what to do... I should eat, I know that. I'm already anemic so my diet doesn't help at all, but I just hate eating so much. And I can't ask my parents because they don't believe me and just brush me off so...