Don't worry about something that hasn't happened. What is done
cannot be undone, right? So, relax. Just hope for the best and if
it turned out not so good, you can always re-sit. It's not the end
of the world.
If parents or teachers are disappointed or grumbles or complains,
let them. It's natural. Just take it that whatever they say, even
if it hurts, ultimately, they actually wish the best for you.
Good luck. Please don't lose sleep over it. Every experience is an
experience. Most importantly, we learn from it. Nothing is a waste.
It will really be a waste if we don't learn anything from it.
Take care and calm down, okay?
Nite nite.