Are you drinking on an empty stomach ? That's pretty important.
Are you regularly taking any other drugs, meds, alcohol ?
What different amount have you tried ?
Are you drinking it and then being active ? or drinking in a settled and chill environment ?
Do you notice your sleep being heavier, even if you don't feel notable effects before bed ?
When I first started, I could only feel a glimmer of what could be, it took trying several varieties, preparation amounts and diving into kava 100% before it became strongly effective.
Your best bet would be to hop a plane to Port Vila and chug 4 or 5 shells over there, that should get ya going.