Childcare fallen through & unpaid time off

It's all sorted now, but I want to know for future instances. My little one (22months) goes to a childminder 2 days a week and is with my parents 1 day. The childminder had to close this week and told us on Friday. My parents/husband would usually be my backup, but husband is working away and my parents were going away on holiday (after their 1 day looking after my son) So, I gave my headteacher advance warning on Friday that I may have an issue Tues/Weds and if I couldn't find childcare, would need to take unpaid leave. Said I would keep trying to find an alternative, but also worked out how we could cover my absence if necessary (so fixed the problem). He replied that I could have Monday morning but would need to be in on Monday afternoon, and that it was important to be in school on Tues and Weds. Monday was never an issue. I didn't know what to do, and wish I'd just called in sick on the days, but I wanted to be honest and give as much notice as possible. My parents ended up cancelling their holiday which I feel awful about, but very grateful. They didn't want me to find an emergency childcare and my son be somewhere he doesn't know, with people he doesn't know. What do I do if in this situation again? Bring him to school with me?! 🤦‍♂️