As a team lead, one question I always ask in my 1-on-1's: On a scale of 1-5 (low good, high bad), what's your stress level since we last met? If my teammate says 4 or 5, I ask what we can do to bring it down to a 3. We also address this as part of the simple assessment we do in each sprint retrospective. My company struggles to define meaningful KPIs and OKRs. This is the one that's most important to me.
Welcome to impostor syndrome!