How do I increase my IQ?

>take IQ test as a 10 year old
>125
>take (internet) IQ test now, 95

I genuinely feel dumber than I was a couple of years ago, my mind feels slower and basic math is harder to me now. I know 125 it's not an impressive number but I was wondering if theres is a way to be "smart" again.
I'm about to enter to university so that's why

Also pic related it's literally me.