Sleeping Scare

So back in early January, I woke up in the middle of the night and had serious stomach pains. I went into the bathroom and next thing I know I’m on the floor kicking and shaking while not being able to breathe. Of course I was panicking and was scared I was dying. I went to the hospital and got check (I’m fine. It was just that I woke up while the rest of my body was still unconscious) Anyway, every once in a while I’ll wake up all of the sudden in a panic or be at school and feel like I’m having trouble breathing just like I was before, but only for a second. Any idea what’s happening to me?