This Can't Be First Love(2020)

Koi de wa Nai to Omoitai

Keiichi and Sota have been friends since elementary school. Despite Sota's popularity with girls, he has rejected all of their advances, and even actively avoids them by hiding in the school nurse's office. Keiichi feels a twinge of jealousy when Sota starts getting along with Jou, a female student who also spends time in the nurse's office, but it may be thanks to her that Keiichi comes to terms with how he really feels about his long-time friend...

(Source: Animate International)