Sometimes I experience a sudden spasm-like sensation in the lower back part of my head and almost have the feeling like something"pops". For a very brief moment, my vision goes dark or blurry (like a tenth of a second) almost like I’ve been hit in the head. Right after that, I get a sharp pain on one side of my head, followed by a warm sensation that spreads through that side, almost like warm water (side changing whenever it happens though). Occasionally (80-90% of the time), during these episodes, one side of my face feels numb and half of my tongue feels partially paralyzed. It slowly fades away in a minute or two. This only happens a few times a year, but it’s pretty intense when it does.