You did the right thing by telling your parents. Even if it wasn't the same guy, this guy yesterday was still freaking you out.

Buy some pepper spray. I keep a thing of it on my keychain all the time.

Will you get in trouble for having that on your keychain in your locker at school? I know security things are a lot stricter now than they were when I was in high school (I graduated in 1999, two months after Columbine, and obviously well before 9/11).