[quote=@Nightmare Bunny]
<Snipped quote by RainbowReindeer>

It's really dramatic... ;u;

Wanted to comfort her -> didn't know what to do -> awkwardly hugged her -> she started crying and went to shower

...I suck at this.

//failure
[/quote]

Hey, I'm sure you did all you could at that exact moment. There are two reasonable paths to go down - leave her be so she can recover or console her to try and make her feel better.

I believe in you, no matter what route you pick :D

Edit: I do advise the first path, and your sisters advice is right, so I can't disagree with her sentiment.