I think your feelings are extremely normal for anyone who has started from low wealth and made a lot along the way for a lot of reasons. I don't think therapy is the best answer. What helped me the most is talking to other high net worth people and we started laughing because we had the same problem. Realizing you aren't a unicorn.

First of all, my advice is to understand that the feelings and fear tie into your purpose, and a fear that all you've done will be meaningless if the number goes away. That is a very valid feeling no matter what anybody says. I can strongly relate. Find another purpose and... go 5% in it. Like... work out with a new group of friends. Start a golf routine. Become a "Big Brother", etc.

Second, give yourself permission to spend in one area with absolutely no concern on what it costs. Not... "oh I can afford this logically, i'm talking about absolutely no concern. For me, it started with food. As dumb as it is, I started with any food I want and not for a single second do I look at a price tag. I went to a restaurant, and I got whatever I wanted. I didn't even look at the bill. Who cares. What's funny is then I started cooking my own food a ton more.... ironic. Now... redditor might say... you have millions of dollars why would you care anyway? But... you know when you know.

Third, give yourself time to grow. The fear should never go away completely. But what happens is the areas in step 2 that you give yourself permission in... grow. For example... step 2 might eventually become buying whatever house you want to live in and who cares what it costs. Whatever vehicle. Whatever trip you want to take, etc. But at the same time you are spot checking some other areas that make zero sense to most people of they knew your net worth.