Kopophobia won't go away

I recently discovered I have Kopophobia. A fear of fatigue or exhaustion.

I already noticed years back that I have severe anxiety because of this irrational fear, but I didn't have a name for it. I was hoping it would just go away on its own if I forced myself to live life normally, instead of giving into it.

((((( TW for the backstory, just in case.
I developed this phobia after becomming very physically sick for about a year or two. The illness was so severe that I was bed ridden most of the time and the fatigue it caused regularly made me unable to do things like speak, read, write, watch movies or even think. )))))

It was quite a traumatic experience, so I understand where the fear of becomming exhausted comes from. But I did my best to not let control my life.
As a matter of fact, I became a workaholic for over a year afterwards. I did a lot of physically and mentally demanding work every day and thrived despite of it. I have proven to myself that I can survive tough work schedules and everday life.

Now my life is balanced, and I work neither too little nor too much. But I still have anxiety before every little thing I do, as if it will cause me to drop dead from exhaustion. It makes me avoid many things. Even fun things, like movie nights. And I yell at people a lot when they give me tasks. Even if it's something really small and insignificant.

I don't want this phobia to control my thoughts anymore. Jumping over my own shadow every single day for the smallest of things is so draining.

I just don't know how to finally get rid of it. I already exposed myself to the thing I'm afraid of for several years. But my brain just won't learn that I'll be fine.

What can I do?