Not hungry and eating makes me sick, why?

I'm am 16 years old I am on dance team and I consider myself a healthy person but the past few months I've noticed that I'm not notmally hungry and when I am hungry I get the felling that I'm very hungry but then only end up eating two or three bites of my food.I've always been a picky eater and have always eatin like a bird(eating a little bit alot of different times) but never really felt like this.when I smell certain foods it makes me sick to my stomach and the foods my mom makes that I loved four months ago make me feel sick but I make myself eat them because I don't want her to think anythings wrong.I don't think I have anorexia because I'm fine with my weight and I'm not sad or depressed .please help me figure out what's wrong