Although cervical cancer
is the most common cause for bleeding after sex ,however this is not the only reason.
Other common causes include
Precancerous changes in cervix
called as cervical dysplasia
Sexually transmitted diseases
Uterine polyps and uterine fibroids.
Since it is beyond the scope of this forum to discuss it in length about each condition,I advise you to consult a Gynecologist as early as possible and subject your for physical examination and relevant investigations.
Once the diagnosis is made,proper treatment can be instituted.