Eye problem? Help!!!?

Today I was about to start to play badminton (for gym cl, 1st hour) but then my vision turned black and I felt like I had gotten a minor full body shock. This experience lasted for about 10-20 seconds, and I couldn't really see anything period, like when you close your eyes. I do where gles, and this has happened to me before but it was only where only half my vision went black. I am a 13 year old male.