Best advice I can give is to 'shout, shout, let it all out'. Let out all the demons in your head and heart. Do it here, or with a therapist, or with confidants. But don't hold onto anything inside of you.
"You're as sick as your secrets"
Another thing that I am also learning (which you are asking about) is that to live in my head is a detriment to my enjoyment of living life and connecting with others. I'm learning that I need to follow my heart, and let go of my expectations (thinking).
I've created a new mantra for myself - Live in the present, follow my heart, and let go of the rest. I get into trouble when my mind tries to 'figure it out' and tries to force solutions and control and manipulate and worry. When I act out of fear (mostly driven by thinking) then I am cutting myself off from all the possibilities that might make themselves available to me if I were to follow my heart.
But how do I know what is in my heart? That's another great question and another subject. Sometimes, I have been able to discern when it is an ego driven desire as opposed to a heart inspired longing. It has to do with resonance. When I sense a longing of my heart, there's a resonance that occurs, and it moves through me.
I wish I had better words to describe this, or wiser words to share with you. But I'm on the same journey you're on, and that's what I've found so far.