Horizontal then Vertical Loop help

Hi,

I am trying to code a loop that basically looks at a start date and then an end date, if there is a gap between dates the loop will then +1 on to the start date in each column until it equals the end date. This will be filled out horizontol starting from column F.

I then need the loop to go down a row and start that process again.

I've attached the example workbook of data i need to apply the loop to.

Important note, the number of rows will be variable each time i run this report, i have already dim'd this variable with the below code

Dim totrow As Integer
totrow = Range("a1").End(xlDown).Row

I am pretty much a beginner when it comes to loops so i have no code for this (no idea what to do!)

Any help is appreciated.