Why haven't I had much of an appetite lately?

Since Saturday I’ve been losing my appetite shortly after eating. I was really hungry Saturday morning so I made some eggs, hashbrowns, and some turkey sausage. I ate a little bit then got really full and lost my appetite. I would usually be able to finish it, but I ate not even half of it and felt like I ate a big meal. I have a high metabolism, so I usually eat more than 3 times a day. I’m almost 28 and I don’t remember this ever happening, so it’s really weird to me. What is wrong with me?