severe abdominal pain... miscarriage?

I am a healthy 25-year old and I am just about to describe what happened to me about a year ago because i can't get it out of my head.

I have to note that I had been equally healthy back then, I had had a perectly normal abdominal ultrasound scan a couple of months before the incident and everything seemed to be fine.

It was the 2nd day of a delayed period and I had just gotten up when i experienced severe abdominal pain that felt like being stabbed on the lower left part of my abdomen. The pain was severe but it came and went in waves, varying in intensity. I had never felt such a pain before, it was neither constipation pain, nor period pain. It felt like being stabbed and it was clearly located on the lower left part of my abdomen, maybe radiating towards my crotch.It all must have lasted no more than 15-20 minutes but it was enough to make me sweat and scream with agony. The relief came gradually after 2 bowel movements and a change in the flow of my period. My period was really heavy and full of fleshy clots for the following 48 hours and despite feeling really weak, i experienced no more pain whatsoever. As a matter of fact, I was able to go to work on that very day. I haven't had anything like that happen to me ever since. My periods are regular, with medium flow and minimum pain. What could have happened back then? Could it have been a miscarriage?