What Causes Irregular Periods With A History Of Pelvic Injury?

I'm 18 and this past year I've had a total of 3 periods. I had my hormones checked and my estrogen was normal and my testosterone was a little bit higher than average, but I don't have any abnormal hair growth, weight gain or acne...I also have hemorrhoids but I've never strained for a bowel movement... I was involved in a car accident almost 2 years ago where I received a small frontal lobe concussion and I fractured my pelvis...those are the only injuries that I figure could be related. Should I see a doctor?