Read these classic philosophy books for happiness

Epicurus - Principal Doctrines.

Five Great Philosophies of Life - basically it Epicurus, Stoicism, Plato, Aristotle, and Christianity. If you can just ignore the rare Christian meandering, it is a good survey. Otherwise, find something that covers these topics. Why? Because it can help you look at the different questions you have in your mind.

Bed of Procrustes - Nassim Taleb. Basically most of the books he writes have been good. This book is condensed aphorisms.

Tao Te Ching - Stephen Mitchell translation. If you are just starting out, this book can be pretty opaque. But is a classic for a reason. Kind of like the basis, while Rumi is like a very charismatic friend who says a fraction of the same things, but does so in a captivating way.