Okay, what is this?

So lately I often feel bad when I'm eating, which results in me not wanting to eat. So to explain it: when I wake up, I feel fine and I do what I always do. Then I have breakfast and then I suddenly feel worse. Then like half an hour after I ate, I feel fine again. Then when I get hungry again, I don't feel like eating because I know it makes me feel bad so I prefer snacks, but guess what, we don't really have any snacks so that's not a possibility. So then I eat and I feel bad again, so I eat less than I really need. Then right before dinner I'm goddamn hungry. But once I hear dinner is ready, I feel bad again and then I try to eat an amount of food which I won't regret and so that my parents won't comment on it. That's quite hard by the way, and annoying as well because I go to bed with an empty stomach and it's annoying.