The Monday motivator goes out to all the persons evaluated in the past 4 weeks or those who have some waiting evaluations and projects (for Premium and Enterprise plans) at risk. If you have not been evaluated in a while, encourage your manager to leave you feedback soon.
You can also check your notification settings to ensure you have not stopped them. Click on your profile name from the top right corner and select notifications. Enable the Monday motivator email notifications if they have been turned off accidentally.