Thanks for the query.
The possible causes for your problem are:
-Structural causes like fibroids, polyps etc.
So you once consult gynecologist, get examined, go for ultrasound
and if needed go for hormonal profile.
With this workup the possible cause for your problem can be identified and treatment can be given accordingly.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429