Thanks for the query.
The possible causes for the bleeding are:
-Local causes like cervical erosion, polyp etc.
-Dry vaginal mucosa due to perimenopausal state.
Mood changes, menstrual irregularity, head ache etc can be seen in perimenopausal state due to hormonal
But as you are having post-coital bleeding, better to get examined to find out the possible cause and take treatment accordingly.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429