What Causes Clots With Bleeding During And After Intercourse?

Hello! I'm 26 now and married 2008. Since a month i'm seeing clots and bleeding during and after intercourse. However, the bleed and clot are only few and without pain, i'm much worried. i'm using thyronorm 25mcg and atenolol 50mg since a yr. i consulted gyno last week and she said no problem in vagina and uterus. Please tel me what could the problem?!.