Constantly thinking.

Hi im male 30 years olds, healty and sober, not on any medication, can you please recomend me something that will silence my thoughts, i just want to exist without constantly thinking / imagining scenarios. All natural things like meditation, mindfullnes, exercising, yoga, doesnt work i've been doing them semi consistenly for years now. Theanine also doesnt work. I just need something that will make Silence in my head...this is terrible way of living.