I'm going to tell my sister and my best friend they ruined my surprise bachelorette party and if they can't be civil I will cancel my wedding
Why would you go as far as canceling the wedding?
It's so frustrating when they can't get along with each other
Your sister and your best friend should learn to behave themselves around each other. But that's a rather extreme reaction.
I'm not sure what to do anymore. I'm looking forward to my wedding but all these women are causing me problems.
I understand the frustration but you don't need to go to extreme to make them feel guilty by cancelling your wedding. You talk to them individually and let them know your concern.