From the third column: why pack in individual days? I can't imagine it being very easy to display multiple appointments there, you'd run out of room.

Do people really care about the exact day number that something is on? How about just displaying items in order under "second half of April"? Then you won't have space wasted if there's aren't any appointments for a few days, but the data is still there. And perhaps show the day number on hover or something.