chan2's answer is correct on grammar, but not so natural. There are many way to say this sentence. If I translate it,.. for example, 私がどれだけ傷ついているか、なんで誰も分かってくれないんだろう。 Watashi ga doredake kizutsuite iru ka nande daremo wakatte kurenaindarou. Watashi ga doredake kizutsuite iru ka = how much i hurt Watashi = I doredake = how much kizutsuiteiru = hurt nande = why daremo = anyone wakatte kurenai = (someone) doesn't understand, (someone) can't understand you see?

Well, I'm not a native, but perhaps I can help you.. なぜみんなは私がこんなに苦しんでいることを気づいていないのか naze minna wa watashi ga konna ni kurushinde iru koto wo kizuite inai no ka? are you talking about yourself? at least I know you are hurt ^_^ just kidding ^_^ ganbarou!!

oops it's not を、but に sorry...

chan2, you're welcome. your japanese is really good, I think. どういたしまして。 日本語、お上手ですね^^

Yeah, I think using "dore dake" is more correct too. So it feels unnatural, huh... 日本語はやっぱり難しい！！www Thanks for your correction Kazma-san, 勉強になりました♪♪