If you want something short, check out the enchiridion. Enchiridion means 'manual', apparently, and is really short/concise though profound and not grasped easily on just a first read

The translation I used to use is somewhat archaic so I recently asked here for the best translation of it: https://www.reddit.com/r/Stoicism/comments/nexdez/best_trans...

I'd take your pick out of these 4: https://enchiridion.tasuki.org/display:Code:ec,twh,pem,sw/se...

Well, the book is a proper tome, but the section on Stoics is very concise (as is rest of the book, really), so I'd go for "A History of Western Philosophy" by Bertrand Russell.

The book also gives a good context on where Stoicism arose, so it might be worthwhile to skim the sections before, though there's no need to get too deep with, say, Aristotle's metaphysics.

It's on archive.org: https://archive.org/details/westernphilosoph035502mbp/page/n...

No. it's not actually mentally healthy. Go with mindfulness and getting in touch with your feelings instead.

No can do. The whole thing is a get rich quick scam by Marcus Aurelius.