Recently, after having intercourse with my girlfriend (I was holding my breath as I ejaculated), I immediately stood up, then bent down to pick something up. I got light-headed and tried to lay down. My girlfriend says that my eyes began to roll back into my head and I was shaking for about 10 seconds. Then she says I dropped my head down into the pillow, exhaled and didn't sound like I was breathing. She tried to lift my head to see if I was alright and I started convulsing for approx. 10 seconds. When I finally came to, I felt like I had just fallen into a deep sleep and thought my girlfriend was just yelling at me. I was completely unaware that anything just happened. What do you think this could mean?
Optional Information:
Male , Age: 32
Already Tried:
Nothing. This has never happened before.