Dad being a jerk-sis always getting what she wants?

so i was making a chocolate ice cream cone and my sister comes in from the backyard crying which is nothing unusual around my house so she says that our dogs killed a bird so i was like "cool now go away i'm eating" (i know sounds jerky but if you knew my lil sis you would act the same way). So she goes downstairs and tells my dad he tells her that apparently both of us are supposed to clean up the bird and again i tell her that i am EATING but she tells me to help put the dogs up so i groan but still go and put the dogs up then when we get outside she has 3 grocery bags and takes one look at the bird and says that she can't do it and i have to since she saw the skull and everything so i say that i'm still eating and that she can do it because she is a big girl now (she is 10 goin' into 5th grade next year) but she shoves the bags at me (i'm still eatin' my ice cream) and says she will be at the trash cans thing is she went the other way (sorry I know long) so i start cussing under my breath (which isn't like me) and finish my cone pick up the bird throw it away stop back into my house and slam the door. Thing is all i saw when i walked in was my sis on the dang computer!! so when i turned around and saw my dad i said sorry and he started yelling at me how i'm 13 and i shouldn't have to be giving an attitude in this house and i should take resposibilty even after i explainded this though him so i started crying (where he couldn't see or else he would start yelling at me again plus again isn't usually like me to cry) and grabbed my book washed my hands and ran upstairs and after a while started typing this. Please tell me what to do i need help badly and don't be a jerk about anything honestly please don't. Thanks.