Stoicism is two thousand years old and still the most practical philosophy I know.
Epictetus taught that some things are up to us (our judgments, actions, effort) and some are not (other people, the economy, the weather). Peace comes from caring only about the first group.
Stoics still feel emotions. They simply refuse to be ruled by them.
"You have power over your mind, not outside events. Realize this, and you will find strength." (attributed to Marcus Aurelius)