 If you liked
Sunadokei
|
 ...then you might like
Koishitagari no Blue
|
They both follow very similar timelines. If you read both, you'll get what I mean.
Both heavily emphasis first loves and true love. Similar to Bokura ga Ita, these three series have a character with a sad/traumatic past, a love interest to their character and another love rival(s). The side male character are all extremely similar as they're polite and kind while the main male character are like a sun to the main female character.