A personal philosophy, or "manifesto" can prove a powerful guide for any uncertainty you are facing. When led by values and ideas that you have chosen, you can dig deeper in moments of distress and disappointment. It can start simply by reframing uncertainty as a worthwhile cradle of possibility and then adding theories, methods, ideas, and values that resonate with you. An uncertainty manifesto brings comfort and calm when we have chosen and experienced its power ourselves.
Without a manifesto (code, belief, or value system--call it what you will) about why and how you are going about your uncertainty possibilities you will sell out or misinvent in the face of fatigue, competition, or any other setback. Manifestos have gotten a lot of people through and over a lot of hurdles.
Don't worry. Religion is not required and the beliefs don't have to be something you have an expert knowledge of. It can be a mixture of things that inspire and speak to you but it must be your own mixture--borrowing someone else's manifesto is better than nothing but work on your own.