What Causes Headache Followed By Numbness In The Feet After Child Birth?

I ve had these strange episodes for 20 years now. They began after the birth of my first baby. A massive head rush/headache followed by numbness in the arch of my left foot. These happen when I ve been sitting for a while and then stand. I have low blood pressure 90/60. They also, however, happen when I turn my neck to the left. The entire episode lasts about a minute. Most of the time I can continue what I m doing, but occasionally I will be stopped in my tracks and need to hold onto something for balance. Had an EEG years ago, misdiagnosed as seizure-I took seizure meds (which didn t ultimately have any affect) for about five years before retesting and no sign of seizure activity. Tested for MS as well. It s a mystery I d love to solve/treat/resolve.