Help ! ლ(´ڡ`ლ)

I'm looking for a yaoi/shonen ai manga I read a few years ago. The story is set in a school and it's about this guy who isn't very much liked and doesn't participate in sport activities. He just sits under a big tree where there is a clover bed and looks for four-leaved clovers.

A (new ?) student approaches him and helps him in his search and eventually they become friends. Thanks to the guy, mc warms up to the other people and they even end up playing together (football I think?)

At some point in the story, mc gets really sick and disappears for a while and the guy sends him a four-leaved clover along with the homework.

My memory is a bit fuzzy but I remember that there was a nurse who helped both of them quite a lot and I think that a black book was somewhat meaningful to the story (I might be mixing up mangas here, but I think the students used to take it in relay and every week a different person had to write something in it ?)

Also.. I'm not completely sure, but I think mc dies in the end..