Keep a running log of your time for each day in Google Sheets.
If
New daily summary is available
This Trigger fires when a new daily summary becomes available (usually at midnight in your local timezone).
Then
Add row to spreadsheet
This action will add a single row to the bottom of the first worksheet of a spreadsheet you specify. Note: a new spreadsheet is created after 2000 rows.
Discover more time saving integrations for Google Sheets and RescueTime