Manga Issue... What should I do?

Another post on the Cubby from me today! I figure I should post here more often xD

But seriously, this question is something important... I've been trying for a long time to create an original manga as most of u know! First my problem was that I couldn't draw but now I've improved there. Now its getting a storyline... I've been partially working on a collab with a dear friend, but I'm trying to get some practice in with this shoujo one-shot that I've announced with this page.

I won't give away details, but I'm going back to my old idea with Yoshi and Ayako, the shy girl who meets a mysterious guy. They kind of fulfill each other during the story, considering the circumstance. In Ayako's situation, she's just too nice and too quiet to say anything so people end up taking advantage of her good works. But then Yoshi comes along and encourages her to speak her mind.
The bad thing is that every way I turn, I get stumped because I think I'm copying other manga ideas @_@ Is it all in my head? no pun intendedxD
Honestly, there are so many ideas already taken that its probably gonna be difficult for any creator to make something completely original. But I'm paranoid about copying other ideas.
Like right now, I'm really loving Kimi Ni Todoke! but before I know it, my storyline has similarities to that series =_= (especially when yesterday I heard in Kazehaya tell Sawako to speak her mind the first anime episode of Kimi Dx) except I never copied it on purpose! I had my storyline of shy Ayako being coaxed out of her shell by Yoshi months ago! I just feel bummed that I get an idea and then I find all those cliches and everything wanting to attach to me.

Ugh sorry for rambling.. I'm still excited to write my manga, but do any of u have advice for me here? Maybe I'm overthinking the 'copying' fact? lol what are cliches right? haha xD But I just get hesitant to start now that it seems similar to Kimi. GAH I always do this.. I get a good idea, and then I hit a point in a new manga thats the same idea I was about to do. So i don't want to do it anymore cuz it'll look like I copied.
Using manga for inspiration is different tho and often helps me along, but I'd never want to rip off a storyline O_O even if I'm just writing an insignificant one shot!

Anyhow, its not a huge deal cuz I believe I can make my story different somehow. But any general advice for any budding creator would be great to hear!!! Thankyou so much for u r time!! <3 ciao!