sorry if i'm wrong....
from what i read...
you two haven't been a lover yet... am i right?

just tell him you cared for him...
tell the truth...
and tell him sorry to bother him so much in his study...

even if you really cared for him...
ask him out dor lunch or dinner on weekend just to tell him you are more than just care for him.... tell him how are your true feelings.

for me, there is a special treat for my lover than only being a close friend~ so, sometimes when i busy, i would just ignore or block my annoying friend but i'll take my time to explain the reason why i'm busy just for my GF... and it works fine~