Okay, so the details are pretty fuzzy.

The setting is in the japanese countryside or something similar...the female main had black hair I think? Anyway, she and her crush were walking along...rice paddies I think? And they had a nice moment, blabla. It doesn't end well? I don't really remember. Anyway, she moves away, and comes back to the same town for college/uni. She gets together with her friends at a drinking party or something, and sees her crush again. But he has a girlfriend, and she's unsure about that moment they had back then or whatever...

I don't think it's a oneshot...>_>

And there was something about a red umbrella? I...I don't know...it had a mellow atmosphere I think...

Possibly the second story Hitotsubu no Shizuku yori in Chuugaeri Heaven.