Bro. I'm an engineer. Have been for more than 20 years. This guy, talking about how his job is harder than someone who delivers packages for 10 hours a day is fucking lying. Either that, or he's completely divorced from reality.
Yes, you need more schooling, and yes, solving puzzles all day is mentally draining. But you know what? I'll take being mentally drained over having my body completely fall apart by 50 because of the toll my job took on it. Being an engineer is in no way harder than any blue collar job I've ever seen.
Edit: And also, if you're mentally exhausted after reading for 10 minutes... that's not normal. Have you been tested for things like dyslexia? Could be that you have some kind of processing disorder that makes it difficult to read.