[BigBiceps]

You can insert a row at the top and it will sum the columns with the function c1=sum(c2:c60000) to sum column c for example.

If you want to see the grand total for each day, create a new column that is for example d4=d3+c4, where d4 is the new total, d3 is the previous total, and c4 is the current session result. Then using the fill feature you can drag this down so it does it automatically for each new session.