I couldn't agree more with Jaxsie. You need to find a Dr. who will listen to you. . It is very possible that you had either a rupture or a torsion. Unfortunately, there is no way we can tell you if it's a cyst or something else. . Do try to find a Gynecologist as soon as you can. .
Hope you feel better,
Sandy
Sorry to say this, but sounds like you need to consult a doc more agressively. If they did not find a cyst before did they find any evidence of one having ruptured? docs can find it difficult to diagnose problems, so you need to be more pushy and say you want some tests. Maybe try keeping a pain diary of when the pain comes and what it feels like- this might help. It could be endometriosis - this cases lots of pain and symptoms that sound like yours, but will not show up on a scan. the only way they can tell is with surgery, but a pain diary would help to suggest a link.
hope this helps,