What should I say to the human leech?

It all started at the beginning of the year. A girl in my homeroom started talking to me before cl, and I was friendly to her of course. She seemed pretty harmless, so I continued to be nice. I figured out soon that her locker was right by mine and we had a few cles together. After a couple of weeks she turned into an annoyance. She would grab me and pull me to the side to just "talk" when it was time to go to cl, interrupt my reading or working to bombard me with questions, and follow me around as much as she could. My friend told this girl politely to leave me alone, but two weeks afterwards she came right back doing the same things. She asked me about my friend telling her to leave me alone, and I said that I wasn't sure what my friend had meant when talking to her. I just didn't want to hurt her feelings, because I don't think she gets to see her friends (if any) between or during cles. However, I know she had several since she has mentioned them ocionally.