[im still not exactly sure how/when to use this, but trigger, i think]

well, im not exactly sure on this, but lately something's been bothering me about when i was like 9 or 10...

once, when i was visiting my dad, he and my stepmom left me at their home with my then 14-ish year old sister while they went to work. my stepsister had a guy come over [i dont think they ever dated] and i think he was a bit messed up in the head... not sure what all was said anymore, but eventually he pulled a knife outta the silverware drawer. i think he was trying to be 'funny', but i got scared, really scared and my stepsister just laughed. i got super freaked when he acted like he was going to like stab me and he held it to my throat so i ran into the bathroom and i wouldnt come out and my stepsister kept calling me a baby and stuff, and i evntually came out when i felt safe. i kept my distance from them until he left.

i never told anyone this, not my dad or friends. i never, ever talked to my stepsister about what happened that day. but like in september last year, i went to my dads, and she was there and i havent thought about since then, but i remembered it and i was afraid to be alone with her. and i keep thinking about it >.<

so, im not exactly sure what to call this. i dont know if im just obsessing like usual or not. whats wrong with me?!
help please >.<
~Danni