Hi
There are few questions need to be answered
How is your sleep? Is it sound or gets disturbed?
Have these dreams started after your delivery(as you mentioned since few years)?
If yes & if its your 1st child may be you are over anxious &stressed about taking care of your daughter & that comes out as an exam fear.
Other possibility is you have certain other stressor in your life which need to be dealt with.
Next Steps
it would be advisable to take professional help so as to do proper analysis & then treatment.
Health Tips
listen to some relaxation music before going to bed
You can take online consultation with me