Don't explain to her why you need that time, just tell her calmly and politely what needs to happen, whilst at the same time acknowledging her needs too, if that makes sense. It could just be a case where your daughter doesn't realise how the situation is affecting you and unless you say something, she will blindly carry on with what she's doing.
That sounds right on to me,
feeling better - even if she gets upset, if you stay calm then it will blow over much quicker. And then if she does accomodate to what you're requesting, its a good time to show appreciation and shower her with a bit of positive attention. Its nice when we get the moments we can appreciate really authentically, hope that happens for you.
If you're texting rather than talking, also its possible to explain at more length without setting off a trigger. Sometimes I'll write up a fairly long text, with paragraphs, and paste it all in at once rather than going back and forth. That way I can sort of explain calmly at length and edit carefully what I'm saying ahead of time.