Same thing happened to me in school, the EXACT same thing. First thing is to focus on the principal of the school because the bully is physically assaulting you and it needs to be reported. I grew up with 2 older brothers and they kicked the crap out of the bullies I had in school. I do believe in defending yourself and taking up karate or other class will not only build your self-defense skills but will also build your confidence. Use social media to your advantage. Reach out to groups: NSA, CampSay, etc for help. I hope this helps