I hated uncertainty when I was young, but I got used to it, more or less. These days I don't think certainty exists. I think the correctness of any assertion is somewhere on a scale between "I've no idea" and "I feel highly confident that's correct / incorrect."
I guess it's a matter of not dwelling on doubt too much, of just recognising it and assessing what's the worst thing that can happen if I act as if I'm right but it turns out I was wrong. Reasonable risks and all that. It's not ideal, but I don't see what can be done about it.
I get the impression that a lot of people pretend they can't fail, as a way of boosting their morale. I don't need that, not because I'm superior, but because I can't need a solution that doesn't work for me. I know perfectly well that I can fail. People who ooze confidence don't sway me much. As far as I can see, they're just faking, maybe even delusional. So I've learned not to need it. Luckily there's this thing where you know you're taking a risk but you continue because your best assessment of the situation is that it's better than avoiding that risk. It's called courage.
But yes, it's complicated when the rug under your feet is always threatening to move. Still, you can do your best to get your way of life more certain. I'm a defensive pessimist who puts a lot of energy into figuring out what might go wrong and taking action to stop that happening. So my life is relatively safe, though it will never be perfectly safe.