What Is The Bright Red Blood Discharge With Implanon Fitted?

I have the implanon birth control and I love it. I never have a period and have experienced no side effects. My boyfriend and I recently stopped using condoms in addition to the implanon. 2 weeks ago I was having some cramping before bed and assumed it was something I ate then in the morning I woke up and there was bright red blood in my underwear. I have not had a period in over 2 years and i did not continue bleeding. was this the implanon flushing out a fertilized egg? I'm not worried so much as curious...