Mental race

I have realised that talking about your problems doesn't help unless you get practical advice and help. I have realised that sometimes there is no easier way of doing what you fear than doing it. I have realised that you can't run away from pain - you have to live it. And I have realised that there is no security and guarantees in the world - and that there is no point in asking for it. My question is: how do I deal with a racing mind? The type that makes you think of everything at once and make you feel nuts. Especially in social settings, where you can't go nuts. I want answers based on experience.