should my feelings be hurt? or am i just being sensitive?

Alright so my boyfriend's sister is getting married Saturday. I was originally supposed to be in the wedding as a bridesmaid but opted out because her bridesmaid dresses were going to be around $600 a piece & my boyfriend & I are trying to save money, buy a house, all that & because all of her bridesmaids are friends she's had for years & they're 25+ years old & most of them are snobby & generally don't want anything to do with me when I go to events with her so I just thought it would be better that I opted out. With that being said, my boyfriend is still in it of course & I'll be sitting with their mother. Today I was told by his sister that because I opted out of being a bridesmaid I would be put to work as in serving punch, standing at the registry, moving chairs & tables & putting them back, doing all the behind the scenes stuff during the reception so I wouldn't have to "stand around". That hurt my feelings because I wanted to enjoy the wedding just like everyone else. I understand someone has to do all of that work but she's hired a caterer & "handymen" as she calls them to set up & what not. On the way home I thought maybe I was just being sensitive & my boyfriend doesn't understand why my feelings are hurt & when I try to explain, it just sounds dumb. Do I have a right to be "upset"? Would any of you ladies feel the same way? What do y'all think? I'd love some feedback!