Am I able to file harassment charges for this?

[Lexa]

Ever since my boyfriend and I had started dating, his ex-girlfriend went completely nuts. My boyfriend and i went to an improv show together at our school, and during the middle of the show, she went to the bathroom and cut herself, and after the show had ended, threatened to stab me. She was in hysterics. I have saved all text messages she's sent me, though i'm not sure they would be considered threatening. Her friends have told me the nasty things she has said about me. She had me blocked on facebook and twitter until new years, she sent me friend requests and followed me. She tweeted me (a random thing, i tweeted something about a band and she felt the need to comment about it). Last night, at a friend's house after a dance, she approached my boyfriend and i and told us we shouldn't have gone, we hurt her, we shouldn't be together. I felt so unbelievably uncomfortable. I'm sick of her controlling my life and getting away with it.
She also sets statuses about us, and tweets how much she misses my boyfriend, her ex. I have a picture of her status that said "I don't care what people say, I miss (my boyfriends name)."

[Exoplanet]

She blocked you, why doncha block her? You are participating in the drama, which reduces your victimhood considerably. You may be able to get a protective order for the threat to stab.

[David S]

She's an emotionally upset, immature high school girl. Her behavior is a reflection of that. I don't think anything she's done has risen to the level harassment as defined by law, but if you want to start making her uncomfortable (which frankly, will only make matters worse and take up a lot more of your time), call the police non-emergency number, usually 311, and make a report.

She can control your life only if you allow it. Disconnect from social media for a while, block her across all of your communications, and then go about your business. You'll learn someday that some things are simply not worth the aggravation.