well it happened again

it happened again, my son scared the crap of me the other night. He was sleeping with me in my bed cuz he woke up crying so I brought him with me into my room. Well any way around 1:15 something told me to wake up and when I did I thought I was repeating the past. My son didn't move when I moved so I started to rub his back and when he still didn't moved I rolled him over and the look on his face scared me half to death, I literally thought my son had died again, so I shook him to where he finally woke up. I was so scared that I picked him up and put him back in his room and then called my husband who is on a work trip 3 hrs behind us. Needless to say I was very scared to rest of the night and after being up for 2 hrs after the fact I finally went back to sleep.
well my son is ok and being the 16 month old that he is.