I just need some answers please

So I am going to turn 17 in January but I started my period when I was 12. I have always had irregular periods. Sometimes I will miss my period by 30 or more days, but I am always late for my period. I had a really bad pain two years ago that seemed to come from my ovaries. It felt like someone had stabbed me. I laid down on my bed, I was so nauseous I thought I was going to be sick from the pain. My mom said most likely it was a ovarian cyst bursting. I was unable to stand up straight for three hours. I never went to the doctor for the pain that I had. I have never been able to tell when I am ovulating. I have experienced the discharge that you have when you ovulate, but only a handful of times. I was wondering if anyone else has had this pain before and if so do you know what it was? Also is it normal to not know when you ovulate?