I am on continuous birth control pills mainly due to uterine fibroids. All of a sudden this week I'm having a period. I have not missed a pill or been more than 2 hours late taking a pill. Is this something I should be concerned about?

Possibly. I'm assuming that you were given birth control pills continuously as an inexpensive way to control abnormal bleeding. You are experiencing breakthrough bleeding on the pill which is common. Birth control pills contain estrogen and progesterone, which may make your fibroid grow. My concern in your case is this: have you had a workup of your fibroid's with CBC, ultrasound, MRI, and hysteroscopy.