Before reading this I will say that English is not my language so pls don't judge me

I know you may hear this all the time from teenage girls, but this bully is driving me crazy. At times she's lovely and acts like a really good friend, but then it switches and she makes remarks and disapproving faces when she doesn't agree. If I do anything, she has a go at me and interrogates me, making me feel under pressure. I've known her all my life, but how can I stop her making my life so hard? I've tried talking about it and making new friends, which does work but how can I get the best friend instead of the spoilt jealous one?
Please help because none of our other friends seem to notice how much she manipulates me. Every time I hang out with her or try to avoid her, she is always being completely unfair and bullies with anything she can find she can sometimes say that I'm fat and ugly when in reality I'm not fat and ugly

what should I do?