Help- TTC

Taylor • Karategirl95

My husband and I decided to ttc our second child, so I stopped my birth control the first of the month. We've had unprotected sex since and during my ovulation time (of course not expecting to become pregnant so quickly after birth control). But this morning I'm spotting light pink and with cm. Ive had cramping and lower back pain but my period is due in 12 days and has always been on time. What could be going on?