What Causes Brain Freeze During Menstruation?

I am 46 years old and for the past 5 years... I have been experiencing mental freezes when I am menstrating. it lasts up to 5 dyas and begins about 3 days prior to my cycle. Is this common and what is the cause.

I am a college student, and really stuggle with common thoughts and issues during this time. Finals are coming up and since i am going into the medical field... I'd like to know what is going on.