Why does my lower abdomen hurt so bad?

Patient: I’m 20 years old, female. My main symptoms are lower abdominal pain, occasional vomiting, almost constant nausea, and worsening fatigue. The pain is exactly where menstrual cramps would be , but its sharp and infrequent. It’s happened maybe two or three times a day for six or so months now. A few doctors have told me that its just residual effects from the Depo and from an ovarian cyst and both would be resolved within a few weeks of taking an oral contraceptive. Now it has been a month and the symptoms are the same if not worse. I just want to know what else it could be, but I can’t find a doctor willing to discuss any other causes.

Symptoms: Lower abdominal pain, occasional vomiting, constant nausea, fatigue