I take creatine daily, have done for well over a year. I also run 5-6 days a week and lift twice a week.
I’ve previously stopped taking it for a couple months and noticed no real difference in physical or mental ability.
The only difference I notice is a small increase in muscle strength after taking it for a month or so.
You may not have taken enough. You need 15-20g/day for mental benefits. And long term, at least 2+ weeks.