Could RLQ pain be chronic appendicitis?

Hi doctor,

I am a 15 year old female and have been having RLQ pain for nearly five months. I am physically fit. I do exercise at least six days a week and eat quite healthy. I have a sharp stabbing pain at McBurney's point. I also feel immense pressure at my RLQ like someone is sitting on my stomach constantly. I had an ultrasound to find appendicitis. But, they found enlarged lymph nodes and said they would become normal soon. I did not have cold or anything in the past two to three months before this happened. It stopped hurting for about three days and then started hurting again, this time without the pressure. Within the last two weeks it has become worse than ever, it hurts. I am always feeling nauseous, even when it is not hurting. It hurts daily and sometimes causes me to double over for 10-15 seconds. It has nothing to do with monthly cycle at all and does not seem to react with food. This Monday morning I had to stop my fitness training as it was so bad and could not complete the session, which is very unlike to me as I enjoy fitness. I have had two ultrasounds and could not find appendicitis or anything else wrong. Also, I have had two blood tests done for appendicitis and that showed slightly higher amounts of white blood cells, but that is not enough for doctors to diagnose as appendicitis. I went to ER at 3 AM; they did more blood tests and sent me home about three months ago. Could this be chronic appendicitis? I do not know what to do and the doctors seem to think that I am making it up. Please help. Thanks.