Be it work or (more likely at the moment) home, handling stress is a really useful skill.
Good news is there are some straight forward pointers to follow.
Firstly, do your best to deal with things in the moment, this will stop issues and frustrations accumulating. When something happens you’re unhappy with, call it out.
This means stating how what’s happened has made you feel plus how you see it impacting on you. What you want to do is open discussion and negotiation. Even if that’s with your 3 year old!
To do this you need to be calm. To take a breath if need be. Remember that if you get angry, raise your voice and become stressed, the situation is likely to escalate. Look to talk to the other party/parties in a reasonable & gentle way.
It’s very hard to argue with someone who’s reasonable and making pure statements. Start making it personal towards the others person/s and you lose your advantage.
Often you’re attempting a sales job. How can all parties get their needs met? More often it’ll be a case of you do Y and I’ll do X. Then everyone gets to feel it’s been a good outcome.
Bottom line is, the more you get wound up and show it, the more likely it is the situation will become difficult and heated. Therefore, take the lead, be calm and reasonable, find the way forward that works for everyone. You’ll feel much better for it.