I do know what you are feeling. I too suffer(ed) from it. It is much better now, but years ago it was almost debilitating. With me (my feelings) it was the most stupid, ridiculous fears. Couldn't figure out why it was happening.
My dr. is very good and recognized it and put my on an anxiety rx. I was reluctant because of addiction scares and decided that I would ONLY take when it the fears were extreme and unfounded. This seemed to clear some of the cobwebs and allow me to see what was bringing this issues on. Some were really obvious once I was able to take a step back (without the fear voices), some were physical, less obvious.
I am by no means advising meds. Just sharing what worked for me. I also did a lot of "self talk"(mantras of sort).
I will give you an example. I feel completely out of control driving on they freeways here (big city), but recently I have been forcing myself farther and farther out of my comfort zone. My "mantra" has been to keep saying to myself "what is the worst that can happen?" and then go through the possibilities. Most of them are no biggie - what if I get lost? Well, I get lost. I will and can find my way home.
With regard to your fears that you have control over - ask yourself - are you doing everything you can to the best of your ability to take care of these things?