I'll give you two major bits of advice to help in case you havent' solved this already:
1). If he walks up on you again, the moment he's close enough, take the heel of your palm (the meaty portion close to your wrist), and shove it in his adam's apple as hard as you can. He's guaranteed to drop to the floor, and it won't kill him. Plus, you won't get in trouble because he's threatened you before, and you had reason to fear for your own safety (God I love that excuse)...
2). Just give me the addy to your school and the name of the bloody bastard. I won't touch him, (since he's probably alot younger than me), but he will not bother you after I have a chat w/ him- guaranteed.
*slips Reaper a katana*
*walks off whistling*