I'm a 19 year old female. For the past three months or so I've been feeling very cramp-y, with pain in my abdominal area and my lower and upper back. I have also had frequent/painful urination and a feeling of fullness in my stomach. My period has been very irregular when normally it's spot on. I have also been having stomach pain after intercourse and a dramatic loss of appetite. I feared pregnancy but I took tests and they came up negative, I really don't think that is it. Could I possibly have an ovarian cyst/cancer?