I have just had an ovarian cyst ruptur and i had lower abdominal pain. I thought it was a urinary tract infection but when I went to the gynocologist a sonogram confirmed it had ruptured. There was a lot of fluid where there normally is none. Don't worry because it seems to be a normal occurance and the fluid will just incorporate itself back into your system. You will probably feel bloated and tender in your abdomen but it will go away.
My gyn explained the "linear structure" to me like this - it is like a collapsed balloon and the measurement is the little "shell" of the cyst which is now just flat and "linear." It makes sense if the cyst ruptured that you could have some free fluid in there also, same for the pain and nausea.