So I called FI's mom on Sunday and apologized for being short with her. I also said that I have a lot going on and don't need to be stressed about helping her plan the party with my mom and sister when I am the guest-of-honor. She agreed and said she was sorry for her behavior and that I am right, she is planning the rehearsal dinner and finding us a cake baker and she should focus on those tasks. I said if she still was hurt, she could call my mom but I am not getting involved any more than I already have. She said forget about it and she is very sorry for stressing me out. Whew!