What would you consider to be your deepest fear?

My deepest fear has to be the fear of regret.

When I am faced with a tough choice, a choice between something that I truly want for my life, and something that I already have but would have to give up for what I truly want, I always feel an enormous sense of fear.

My mind starts racing with thoughts of regret.
I start thinking about what I currently have and that I will have to give it up, but not just that, I think about the fact that I won't have it anymore, that I won't be able to do the things I do now, I imaging all of the things that I will not have anymore. I question myself about what I will be missing from life, who will be hurt by this choice, and most importantly, what if I can't get back what I give up afterward? What if later down the line, in the future, I decide that I want to go back to what I had and it will no longer be available, what will I do then? That is the point of regret, and that is the feeling I fear most.
To imagine how people would feel who are impacted by my choice creates a traumatic fear in me that I just can seem to get past. I imagine their pain and the fact that they feel it and that I caused it. The moment these thoughts pop into my mind is the moment the fear takes over my decision-making.

When I am faced with situations with choices like this, I am filled with fear. I am filled with an uncountable number of questions all sourced from regret, all based on the question "what if?".

This has evolved from just fearing regret into fearing that situation where I fear regret. I fear fearing regret.