I found this manga on here ~5 years ago on a forum. Unfortunately I can't find the forum anymore but It's about a pair of childhood friends/next door neighbors. The genres would probably include mature and romance. It also includes sexual scenes so the tages might include smut? The male lead is a gloomy bookworm type guy, with black hair and glasses. The female lead is athletic, and she has really short hair. The guy is very tall and the girl is pretty short. It takes place in highschool, and the girl competes in track/cross country competitions sometimes. They are in love, I think, or have some type of relationship. Their relationship is really toxic and the male lead often gets jealous. They don't confess to each other or get together for a long time, but it was a finished series. Please help 🙁 I had a dream about this series and really wanna read it again.

Could it be Watashi no... Megane-kun ?