Someone is harassing me for being too close to her partner

i became friend with this guy for half a month. weve been talking and sending everyday pictures since then. we went out for a drink twice. we never talked about our current relationship status. i have a boyfriend and he has a girlfriend. i didnt know he was in a relationship, i only know he has a son. i didnt checked his facebook wall and scrolles on photos since i see him everyday at work. we didnt really flirt much, we were just so close. then one day he went home drunk and his gf saw our fb mesgs. she got so mad and threatened me a lot. she posted threats on fb and even messaged my friends and boyfriend. she kept on scaring me even though i apologized and told her we were just friends. can i sue her for threatening me? i wasnt even able to go to work with fear she'll jump out of nowhere and make a scene. she calls and text me every 4am and tells me this and that. i havent really slept. im so afraid of her because i feel terrible that she says i ruined her family. the guy send me mesgs that everything will be ok. that i shouldnt be afraid because we are just friends. is there any grounds for her to sue me? or for me to sue her for this?, thank u

Simple unjust vexation case only. The problem is that the penalty is not so harsh. It will give you a 2nd thought whether to pursue the case or not based on its practical application.