Your "mental wellbeing" is about your thoughts and feelings and how you cope with the ups and downs of everyday life. It's not the same thing as mental health, although the two can influence each other.
The Stirling Children's Wellbeing Scale (SCWBS) was initiated by the Stirling Educational Psychology Service with the objective of creating a holistic, positively worded scale measuring emotional and psychological wellbeing in children aged 8 to 15 years. This scale should provide a useful tool for education professionals to assess any changes in wellbeing from a mental wellbeing perspective.
The WEMWBS is a positively worded scale for the measurement of mental wellbeing. The scale has been widely used nationally and internationally for monitoring, evaluating projects and programmes and investigating the determinants of mental wellbeing. The WEMBS is free to download/use but you must first register for copyright purposes. https://warwick.ac.uk/fac/sci/med/research/platform/wemwbs