I have been losing dark brown blood for weeks 14 weeks pregnant they told me white blood cells on cervix i am being told it could be cervical cancer ?

Unlikely it's cancer: There can be many reasons for bleeding during pregnancy. Cervical cancer is the least likely reason in a 21 year old. Dark blood is less worrisome than bright red blood. WBC's are suggestive of a vaginal infection. I recommend you be examined by you doctor to determine of you have an infection or possibly a clot or small placental separation.