Oh man Cuberdude! Things just aren't going your way lately, huh??
I've honestly been on both ends- the person walking away(you), and the "help" (your sister). It's stressful for both!!
Are you sure it's a break? Not that I'm doubting you, just curious! Basketballers and volleyballers get jammed fingers a TON (believe me, I used to play volleyball... Fingers were constantly hurting, swollen, and bruised :()! I'm so totally sure that you can break your finger in basketball (duh), I just haven't met anyone who has :(
If you sister does act this way, just pity her. BTW, is she older or younger than you?? Might be hormones, tbh.
Just keep your head held high, bro!! Best of luck :)