I'm really sorry you were ambushed like that. Some companies are way too free-and-easy about putting legit porn into "documentaries" just to set the stage. It makes perfect sense for you to have been triggered after everything you suffered.
This next part is easier said than done - like, if most people could do it this website probably wouldn't exist. But still: try not to judge a kid so young through adult eyes. You weren't "gross" - you were abused.
"Don't think it hasn't been a little slice of heaven just because it hasn't!" --Bugs Bunny