I am suffering from abdominal pain and missed my period for two months. Is it due to appendicitis?

Hello doctor,

I am 15 years old. I am having abdominal pain for a month now. Sometimes localized on the right side or left side. Mostly, the pain is all over the abdomen and going to the back and pelvis as well slightly. It is recurring, sometimes serious, sometimes dull ache and sometimes mild. Also, I have not had my menstruation for two months. Doctor recommended ultrasound and ultrasound came with a report of mild appendicitis. I went to the ER, but the pain subsided by then and was recommended to go back home and come when it is severe. When pain gets severe, by the time we reach the hospital it subsides. I went to the doctor again, they gave me pills for irregular menstruation. I have a loss of appetite. I do not want a temporary solution for my pain as I have already visited three different doctors (one in the ER, one who gave Ultrasound, and one who gave hormonal pills). I am having a doubt if it could be pancreatic cancer or ovarian cancer? I am very scared. Also, I have not started the pills yet and it is three months now I did not get my menstruation. My menstruation started three years ago. I do not have diarrhea or constipation. No headaches and nausea.