Whatever your problem is, what you have to do is think your way through it. Maybe you can use some professional help with this.
It's not the quantity of your thinking that counts - it's the quality of your thinking.
How do we do quality thinking? The most important thing is to think calmly. We don't do good thinking when we're upset. I'm sure you know that the worst thing to do in an emergency is panic.
Calming down is actually very simple. I've been showing people the story of how the life of a Marine combat officer was saved by just breathing slowly when he was wounded.
Two psychiatrists, Brown and Gerbarg, say a 10 or 20 min slow breathing exercise - 5 breaths a min - is good and 20 min twice a day is a therapy for anxiety. The exercise is inhale and exhale gently, 6 seconds each.
By the way, this is really good anger management. If you feel like you're about to harm somebody this will cool you down fast.
Thinking itself is calming. When you use the thinking part of your brain, it gets control of the emotional part of your brain. Right away, you go from opera diva to Sherlock Holmes. You analyze the situation, look at good and bad possible outcomes, guess at the likelihood of worst-case scenarios and what you'd have to do in the worst-case.
When you do this, you'll probably see that the situation wasn't as extreme as you thought it was and the need to overthink will go away.
A famous psychiatrist said that when we can't control our feelings we can still control our muscles. If you think you're about to say the wrong thing. you can just tighten the muscles of you jaw and it will keep you mouth shut while you think of the best thing to say, which might be nothing. You can even freeze all the muscles of your arms and legs so you're safe from harming anyone.
Again, you might want professional help. Treatment usually begins by seeing the GP, who can give you a physical and a referral. I mention referral because just a bottle of pills is not a very good approach.
The things you'd want to tell the doctor are how you feel at different times of day and any symptoms you might have like change of appetite or sleep, and things in your life affecting you feel.