Weed is on this planet for a reason, so from a chill perspective here's what I think.... Don't burn any bridges even if the bitch is crazy. Let her know that you are keeping it, but let her know if she ever wants to kick it you would be more than happy to chill with her (and even smoke her out *optional*)
Life is too short to be negative towards anyone. They say it is the art of mental alchemy to transform shitty situations into situations advantageous to you.