Poor appetite

Hi! I'm 16 and I've been having trouble with my appetite. It's not that i can't eat, it's that i don't feel hungry at all. I don't know what it is, I never know when I'm hungry or not. I tried to tell my mom but she just thought I was trying to starve my self to get skinnier. I'm not trying to do that I honestly think something's wrong with me. I don't have another doctors appointment till October should I wait till then to ask my doctor. I need some advice I am a bit worried. I lost 6 pounds in 2 weeks.