Listen to your doctor. It is possible that you may have an appendicitis.

your rebound tenderness test is negative so you do not have any peritoinitis while Appendicitis often cause inflammation in peritoneum,so you do not have Appendicitis!

ive heard ovarian cancer can come outta it.
but i dunno for sure because im just 14 and friends dont really know anything.
look this stuff up on google.

Well I am 25 as of Dec 09, and Dec 28 I was rushed to the ER due to severe pain. I was laying down watching movie and in 1 second I was on the floor crawling, standing, fetal position, anything to find comfort..nothing! I went to the ER could barely wait to be triaged and when I finally got in the room a rush of sweat came on and I vomited about 4 times.I was weak, dizzy, sweaty, clammy, pale. At this point they gave me an IV of dilauted and fenergan to help with nausea, and did some bloodwork. I thought at this point with my "swollen rectum" it was food poisioning. They later made me drink contrast and did a CT Scan where they found 'fluid' in my lower pelvis whish said could be from a ruptured cyst or my appendix. They ruled out the apendix and said "we THINK it was a ruptured cyst." I had another internal and external ultrasound done where they said I have multiple cysts on my ovaries, the sacond ultrasound looks as if it changed dramatically from the first one which my doctor said "she has never seen before". And now we are just waiting. Waiting for my insurance to kick back on, waiting for another ultrasound, all while I have a distended abdomen, pressure, and some dull ache-y-ness. Hope this helps. I still dont have answers myself, as to why I have these cysts how long I could have possibly had them, why did it rupture, can it rupture again, what kind of cysts are they and most importantly is it cancerous?