If religion means for you the idea of a real constructive change of life - rather than (just) a new set of beliefs in the context of exactly the same general way of relating to the world; then you probably need to fix your metaphysics.
Your metaphysics is, in this sense, your deepest and most fundamental set of assumptions about how reality is organized.
Getting this right does not, in and of itself, change you experience of being alive. But it is often the first and necessary step towards making that possible. And, for sure, some assumptions will pretty much sabotage any prospect of a significant and sustained enhancement of your life.
Fixing metaphysics has two aspects:
Negative - means to break bad habits, compulsions or unwarranted/ unnecessary convictions. Such beliefs include the assumption of insignificance - that that nothing really means anything. That all good things are subjective only. That all experiences - no matter how wonderful they feel - are ephemeral only- and will be terminated utterly by death.
That what you thin you know is rendered unreliable by the intrinsic inaccuracies of the senses, by the possibility of illusions, by the tendency towards delusions and wishful thinking.
That we will never know for sure that the whole world and all the people and things in it, and the sense we make of it - isn't just a kind of dream or nightmare.
Positive - means the possibility of building your life around assumptions of significance, meaning, purpose. These would probably include assumptions that you personally, and what you do or don't do, matter in the large scheme of things.
That life has a purpose, and that this purpose includes a role for you specifically. That things (significant in themselves) also add-up to something even greater.
And that you have the possibility of real and valid communication with other people, and things.
The thing we must recognize about metaphysics, is that the metaphysical framework is neither validated nor contradicted by experience. That modern metaphysical assumptions are not the consequence of knowledge, or science, or logic. That traditional or religious metaphysics have never been refuted nor disproved.
We can choose to change are metaphysics, and (by repetition and self-monitoring) work to make the new metaphysics a spontaneous habit.
Is metaphysics then all just a matter of arbitrary opinion? Well, it can be but it need not be.
1. We can examine our metaphysical assumptions to see whether they are internally consistent and coherent.
2. We can trace the provenance, i.e. the origin, of the metaphysics we currently hold-to and see whether we regard that source as good, reliable, trustworthy (for example, if the metaphysics comes from people whose motives or character we regard as bad, then there is a good reason not to accept their metaphysics).
3. We can explore and compare the consequences of different metaphysical systems and evaluate which we think is the most Good: that is, the most true, beautiful and virtuous.
In other words, we can approach metaphysics with the conviction that some systems are better than others, and deploy our deepest and most fundamental mode of evaluation to compare systems and choose that which is best; and choose to try and live by it.