I've been known to think myself in the ground.
One thought or idea placed in my head can consume me sunup to sundown. Overthinking has plagued me since forever. I've always been introspective and analytical, but that's not always a good thing.
Overthinking can put you in a state of inaction. As a matter of fact, overthinking can simply be an excuse not to act because you're afraid to move or fail forward. If you're an overthinker like myself, please understand that this is not something that you will break out of overnight.
However, you can make steps to get out of your head:
Relax. This is easier said than done but it's critical. Relax your shoulders, go for a walk, breathe. Don't add stress on top of whatever you're worrying about.
Understand things will be okay. It's all a learning experience, and whatever the outcome, you will continue to grow into the human you want to be.
Take small steps. Action is the key. Just do something. Don't worry about who's going to say what or who you might possibly offend. It is impossible to please everyone.
Document the journey. I've been collecting my journals for 12 years now, and I'm glad I did. It shows me that things I would stress over wasn't that serious and that eventually I moved on to the next thing.
Make adjustments. After you've taken steps along the way, make adjustments and continue to move forward.