I need some advice...?

As you obviously have negative experiences with the girl, it’s not really shocker that you be upset about her and your BF being close. Though I think probably more jealous or upset than angry, but since anger is a part of jealously, you should probably be careful about taking it out on BF, since he only has brotherly feelings for her and doesn’t deserve you taking it out on him and he will not appreciate you bashing the girl. My suggestion is that you find some way to calm your emotions (Writing poetry, doing sports, crying, yelling(at some random wall or something, not a person) playing/cuddling with your pet, talking to a sympathetic ear, ect.) and then try to understand your feeling. You should also put yourself in your BF shoes and try to sympathize and understand his feelings. This will help you in expelling your jealousy/anger/or whatever at the relationship your BF and the girl share. If this stuff doesn’t work you can try talking your BF about it, though I warn you he will probably get upset and such.