When I deconverted, I found the following readings helpful in orienting to a new worldview:
Eliezer’s Sequences. Many of these are explicitly about the problem of finding meaning in a godless world. But even the articles that are not about that demonstrate a hard-to-summarize way of orienting to the world that can be healthy and joyful. Particularly relevant sequences:
Luke’s old Common Sense Atheism blog. I liked following his journey from Christianity to atheism and beyond.
But most importantly, I benefited from talking with friends about the big questions (“How do we feel about death?”), the small questions (“Which religiously proscribed activities are fun, and how do I do them?”), and nonreligious questions that I needed to reexamine (history, politics, race, gender). I hung out with my college’s Atheism/Humanism/Agnosticism student group and the local Less Wrong meetup, where I met some newly-deconverted people.
I was just reminded of this post of yours in the suggested posts section at the bottom of this page. Based on that, I especially recommend:
Reading Existential Angst Factory;
Focusing on solving the biggest practical problems in your everyday life;
Talking to your psychiatrist about experimenting with different medications, if appropriate;
Finding a good talk therapist, if you’re able.