Feeling robbed!

I dont know if im being over sensitive or if i have a point. Im also not really needing advice, even though if i was given some i would appreciate it, maybe just looking to vent. As i titled, im feeling robbed, robbed of those special moments in wedding planning, and by no other than my sister. She literally and ALWAYS makes such a big deal out of nothing, everytime we discuss dress styles, or just go see some dresses since all of our schedules are so different she either makes a show, or is just plain rude!! For example, when we went to a bridal store to shop around for my dress, we were in the car and she literally had a whole argument with our sister and had the worst attitude the whole day, making snarky rude comments to my fmil, store attendants, or even anyone who spoke to her, totally ruining the fun for me, & my mom because she was just so embarrassed . & i think the part that hurt me most was when we went to look at bridemaid dresses and i spent all night making them a thank you / formal bridal proposal box and before they can even open it she caused a whole scene at the shop about how the dress she had on was “horrible” and “couldnt breathe in it” because it was a halter top, to the point of scratching her neck.. it was so embarrassing, it was like wow.. i live in nyc, had a bag full of boxes with my two kids, one in a stroller, took 2 trains in the 90 degree heat to just walk out the store in tears... my other girls followed along and opened their boxes in the STREET, it was so horrible and it totally took away from the whole experience. Sorry for the long post, just feeling so stuck (because shes my sister) but shes all mad now, AGAIN, shes now texting me on a rant because i made an appointment to go see some more dresses and didnt let her know FIRST about the date before i told my other sister & moh so now shes saying shes not going & how shes not important... its so childish i cant believe im even stressing this.. but i am. Ugh