Having low testosterone, constant pain, mental health problems, etc. before and during my vegetarian/vegan experiment seemed like it was "NORMAL".
I read a little bit about the foods I was eating causing inflammation, which has a high impact on all of this, and how keto & carnivore diets were low inflammation, and affected biomarkers that I do not even understand.
I switched to low carb vegetarian, but this did not help much. And it was not satiating. And it's expensive. And, from what I've read from the authorities I somewhat trust, it is not as healthy.
I then switch to all meat (literally steak, eggs, butter, and salt) for a couple of weeks and my mood and body composition improved immensely. I wouldn't recommend that diet long-term, but it made me realize that life did not have to be as miserable as it was on the vegetarian diet...