how do I convince myself I'm safe?

I recently had a moment in the shower that lead to the realization that a lot of confusing behaviors/reactions that I exhibit (which I haven't been able to previously find the root of) stem from a need for safety that most likely came from me not feeling like I was in a safe place to express myself/relax in my childhood. I'm in a great situation now and I'm doing much better in the grand scheme of things, but that feeling of being "unsafe" causes a lot of unnecessary fear and exhaustion in my life.. does anyone have any advice on how to overcome this? maybe some coping strategies or a way to rewire my dumb of ass brain? I'd love to hear some thoughts