may be pregnant

i’ve been on the pill since september, and i missed my period in october and spotted in november. this past month i have missed a pill and have had sex regularly, including when i was ovulating. he also ejaculated in me this month and he usually pulls out. i’m scheduled to start my period on thursday, but today i am spotting brown and i have been cramping the past couple of days and have sore breasts. could i just have started my period early or is there a possibility i could be pregnant? also my period blood usually is red, not brown like it is today.