Hello, My Name Is Sherrie And I'm 16. I Have

Hello, my name is Sherrie and I'm 16. I have been having loss of appetite in the morning along with nausea and fatigue. Do you have any ideas as to what this is? I haven't been eating as much in result of this and I wish it'd stop. Also it has been going on for a good amount of time but never really thought it was a symptom of something.