I would highly recommend you wait until Monday to start Day 46, regardless of what day of the week you finish Day 45.
The reason is that the days are laid out mimicking the days of the week and yoru rest days (every sixth and seven day) will be Saturday and Sunday going forward.
If you don't start Day 46 on Monday, this timeline will get messed up.
Start Day 46 On A Monday - Month 2 · 10k Per Month Agency