I know how you feel, I was so sure I'd given mine too much at first, the effect was so profound - at a time they are usually tearing around the house at waist height they were curled up together on the sofa.
My kittens are just under 6 months but are big and I give them one drop from the pipette each - they very readily lick it from the top of my hand - must taste nicer than it smells!
If I give it to them after eating it seems to take longer to work - maybe just over an hour but if they've not eaten it works in about half an hour. I would give her some tonight or over the weekend and measure how long it takes her to settle and how long it lasts and increase the amount if you need to.

Good luck!

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