IB or early AF

For the last week i have been cramping off and on. My predicted ovulation day was 3/19. We BD 3/18,3/19,3/20. I havent taken a hpt yet but had a blood test done yesterday, im currently waiting on the results but today im experiencing some light brown spotting and is getting lighter and lighter as the day ends. Could this be implantation bleeding? Im scared to test as it may be to early. Im currently 11dpo. Anybody have this before? I need some advice!