I've been searching for hours about this vocaloid song about a guy who can't say his feelings or something like that. So he wears a mask with an x mark and wears the typical highschool uniform. The music video has also predominantly green background. The title also has "W" if it's in romaji (not english) so something like "wakaranai" or smthn idk huhu halp.

(If it helps, I have this picture drawn back when I was a kid.)