I had a huge fight with my bff and I can't stand her anymore
Is there a reason you want to end your friendship?
Sometimes she has really bad manners.
You shouldn't let a one off fight ruin your friendship. If her manners have made you angry, try to talk to her and see what can be done to make you both happy.  She probably didn't realize it was upsetting to you.
Nah.
Please at least consider talking to your friend.  Like you said, this is your 'best friend forever' so you shouldn't let something as trivial as rude mannerisms ruin that for both of you.  When you are feeling a bit better, she'll be there ready to listen.