Best friend no longer

by Rosa
(Australia)

I have a friend who I've known for a very long time, but recently I've noticed she has changed a lot, and not for the better. She has become very self-centered, she sleeps around, uses me as an excuse to be away from home so she can pick up guys and I feel like I don't know her anymore.

The only problem is that she is very clingy and still thinks we're 'best friends'. She calls and texts constantly, and if I ignore her she doesn't take the hint that I don't want to talk to her, she just calls more! And when I finally answer, she'll talk for hours about herself and all her problems, but when I want to talk she changes the subject, doesn't listen or hangs up.

I don't know what to do about her. Since we've been friends for so long (11 years, to be exact), it seems wrong to just cut her off outright, but it looks to me as if that's my only option. Is there anything else I can do?