can someone help me please?

so lately for about the past week, i've lost my appetite and it's basically been I eat a bowl of cereal in the morning, maybe half a sandwich for lunch (I havent eaten lunch lately) and I pick at food for dinner. I usually am very hungry and can eat a lot. And i've also been going to the bathroom more often. Can someone please help me?? Everytime I think of eating I feel like I just ate a full meal and I can't eat anything.