• Get into counseling so you can process what happened in a safe space. Visit your college/university counseling center (where you as a student are likely to have free sessions every academic year), or find a professional in your area or online.
• Read up on your university's policies on sexual harassment and relationships between students and professors.
• Set up a Google alert so you know whenever these stories appear online. Brace yourself. There are LOTS.
• Talk to people. The first thing any predator does is isolate you. Reach out to people you trust and share your story. Do not be ashamed! You are not the one who violated professional ethics-- S/HE IS!
• Document. Start writing down everything you remember about the dates, witnesses, etc. Collect evidence. Print emails. Screen shot text messages. Record conversations on your phone. Save everything!!
• Check out the Resources page.
• Consider consulting with an attorney to explore your legal options. Check out avvo.com to find an attorney near you.
• Consider starting a blog to tell your story, as so many courageous survivors have done. 
• Consider starting a petition with change.org as ASU students did

Bottom line: Don't give up and don't give in. You deserve an assault and harassment-free education.