EDIT
FOUND IT (after fourth hour of searching)
It is Aniya Yuiji's "The Nightingale cries into the night"

I can't find a yaoi manga, it was a story about a call boy that has a sick mother in hospital, and falls in love with the nurse guy at the first sight.
For more information :

1. He once dressed as a nerdy kouhai with bottle bottom thick glasses
2. He once was a dog
3. He also was a "doctor" once

Last one the nurse guy hired him as a "chair"

PLEASE HELP!
I loved this Manga, been looking for past few hours and can't find it!