What Could Cause Tiny Intervals Of (split Second) Feelings Like

What could cause tiny intervals of (split second) feelings like the brain totally stopped, or black out without ever losing consciousness while I'm at the office working or home doing household chores, or split second amnesia that occur 4 or 5 times a day. I'm a 51 yr healthy female & have NEVER taken any drugs & do not drink alcohol. The only main health issue going on with me currently is daily tension headaches & migraines ( which started at the age of 9) These episodes occurred have off & on the last year but, More so-just recently.
Sincerely Delilah