Hi, Maybnxseasn!
Welcome to the forums.
Well, here is my answer, if you refer to "drowsy" and or to "a sleepy expression" you can say,
adormilado, somnoliento, soñoliento
I you refer to the eyes,
ojos de dormido
to be/feel sleepy is
tener sueño [literally "to 'have' sleep(iness)"]
to look sleepy =
tener cara de sueño [to 'have' a sleepy face]
Example,
I always get sleepy in the afternoons = siempre
me entra or
me da sueño por la tarde.
Hope that helps (let me know if any further question... before I go to sleep!
)