Impostor syndrome and my experience learning a new technology

I finished the university and got my B.Sc degree not being the top of the list, but not being among the lasts either. However, being most of the time surrounded by people that are smarter than the average, I slowly developed (what some call) the impostor syndrome.
Being in your early 20s and trying to find your way in the society (a.k.a getting a job) while doubting every single thing you know or do is not a fun experience.

Years passed and I found a niche to exploit working as a developer for over 6 years now. I got thrown into random technologies without training or time to actually learn it. "Learn it by doing it" I was told. And so I did.

I am currently considered a key developer in the company, my work is "valuable" and yet every day I live with the feeling that "I have no idea what I'm doing".

I didn't develop anything at home so far. After being 10-11 hours at work, I couldn't deal with anything similar at home. Yet, recently I decided to take on a personal project and learn React by doing so.

Everything went great. My mood was very optimistic, the energy was there and the stars seemed to align. I spent a few hours watching some videos, I started and configured my "Hello world" project and pushed everything to GH.

I spent the upcoming days laying down a plan, decide what was important to focus on, what could come later and what was only "nice to have". I implemented my first component, but it felt a bit hacky and I decided that learning React was my personal choice and I might as well do it well. As a result, I subscribed to a course on Udemy. What better way to learn something from scratch?

And this is where the impostor syndrome kicked in. Again. Three - four hours into the course, trying to follow the basics and my mind goes into the you are not a real engineer mode. I can't follow, I can't learn and all my energy is drained, day and night, by an "invisible force".

It's been not 6 days since I pushed last time to GH. I've been trying since to write a basic component that handles my avatar, but every time I open the IDE my mind goes blank. I can't focus. I'm trying to look online for what others did, yet I keep telling myself that stealing code from SO is what I always did in my career, as this won't work forever.

I was reluctant posting in here. I feel like I'm crying online for nothing while the world has some real issues to face. Yet, we each have our own demons and I have no idea how to fight mine. I want to break the "watch Netflix forever just don't try to code anymore" kind of mood that seem to control my life lately.