I had severe lower abdominal ache:(?

yesterday suddenly i developed lower abdominal ache.i thought it was appendicitis as it was radiating to right side..it was very sever,and continuous.i went to emergency,i was given dicloran n gravinate n 1000 ml saline...dr asked me for ultrasound abdomen n pelvis.pain got relieved after 2 hours..i got my abdominal ultrasound done.dr said its mild pelvic ascites.and left ovarian mass..it can b cyst or mid cycle follicle.my lmp was 13 june 2011...i got my complete blood count done and urine routine examination.ivnt got report yet.bt now m having blotting n mild ache n tenderness in lower abdomen...what it cud b..im afraid..does it happen to girls..why did pelvic ascites develop..help me im tensed..im myself a medical student,,but im just confused