So my child was sleeping for about 15 mins and I go to go to the bathroom and as soon as I get in…

So my child was sleeping for about 15 mins and I go to go to the bathroom and as soon as I get in there he just starts screaming and crying! I'm like wtf? Normally he won't just start off crying like that it builds up to that and idk wtf happened if he startled himself or had a bad dream idk. I'm convinced I'll never sleep again until he's like 13.😫