my family is making me feel like crap! how do i move on from this?

Ok i'll try to explain the best that i can, but what im going through is ever since forever my sister has always had such a dominate personality and it has caused her to take over everything. and i was always the quiet one and easy going about everything. So because of my sister being that type of person my parents always gave in to her in my opinion because she always demanded on having things her way and since i was always the one that was to shy and quiet about everything to speak up it always felt like she always got her way and then when i grew up and begun to speak up for myself they still would give into her and get mad at me if i thought she did something rude or hurtful towards me.  and the most recent thing is over the past few months there were 2 times when she took me and my parents out to dinner and ended up paying for all of us including me and ever since then when ever she does something rude mean or something i think is hurtful my parents get mad at me for getting mad at my sister because they say of well she paid for you. in my opinion just beceause someone pays for you that doesn't give them a free pass to hurt you and be rude to you whenever they feel like it and they think i should look pass her being rude towards me just because she payed for me when we went out to dinner. (and by the way she makes good money)  and am i twofaced when i get mad over something that she said to me and keep it to myself and act like im not mad at her and act normal towards her only because i dont want to create a scene in front of the family? i was called two faced today because i vented it to my mom and had a huge fight over her and thats what my mom is saying to me. so i guess i should say something to her face and create a huge fight in front of my parents and then they will get mad at me for not trying to get along with her! because that has happened before. my parents thing im the one being crazy about all of this when im just sick of her being so rude and hurtful towards me whenever she feels like it. and in their opinion i should look past it because she payed for me 2 times for dinner out of our whole lifes. how do i deal with this? am i wrong here?