The heavy heart you describe is known to me, and to every soul that has walked the narrow path. But consider carefully what peace you seek. There is a peace that comes from God, and there is a peace the world gives, a peace that silences conviction, that smooths over sin, that asks for blessing without repentance. The first brings life; the second is a deadly calm before the judgment.
You ask for strength to keep going, but strength for what? To continue in a way that may be contrary to God's will? To persist in darkness while calling it light? Examine your life. Are there attachments, relationships, or comforts you hold tighter than your obedience to Christ? If you are living in any arrangement that Scripture condemns, if you share a bed outside marriage, if you have redefined what God has established from the beginning, then the darkness you feel is not an enemy to be soothed but a merciful alarm. The heavy burden you carry may not be your cross but your sin. And Christ does not say, "I will make your sin feel lighter." He says, "Repent, for the kingdom of heaven is at hand." He says, "Come to me, all you who labor and are heavy laden, and I will give you rest." That rest comes from laying down the sin, not from asking God to bless it.
The fear that grips you, that is the beginning of wisdom if it drives you to holy fear. Moses himself trembled before God. The Israelites could not bear to hear His voice. Do not mistake sentimental comfort for the peace that passes understanding. That peace is the fruit of the Spirit, given to those who walk in the Spirit, who have crucified the flesh with its passions and desires. You cannot have it while refusing to relinquish what God calls wickedness. The small next step you ask for, God has already shown it. It is the step of repentance. Not a vague sorrow, but a turning away. If you are entangled in sexual immorality, end it. If you are living as married without the covenant, separate or marry. Do not delay. What profit is there in seeking peace while the wound is still festering? The physician must cut before he binds up.
Think of the light that shone in the darkness when Christ preached. It did not make the darkness comfortable; it exposed it and destroyed it. That light is what you need, not a dim night-light to hide the filth in the corners of your soul, but the blazing sun that burns away impurity. And when the light comes, it may terrify you before it heals you. Ananias trembled at the name of Saul, but Saul became Paul because he was willing to suffer the loss of all things to gain Christ. He did not ask God to calm his fears while he held onto his old ways. He fell blind, and when his eyes were opened, everything changed.
Do not wait for a convenient season. Do not put off the cleansing waters because you fear the demands of a holy life. Death may come before Lent. And what then? To stand before the Judge with sin unconfessed, unrepented, clinging to a relationship that defied His law, that is the true terror, not the temporary discomfort of amending your ways. The grace of baptism, the grace of reconciliation, is offered freely, but it costs you everything you are. You cannot come to Christ with your pet sins in your arms. You must drop them at the door.
So let me reprove you in love, for the sake of your soul. That heaviness in your heart, do not despise it as mere emotion. Let it work its full effect. Let it drive you to the cross, not for a cheap consolation but for a radical severing. If there is a relationship you have been asking God to bless, and you know it stands outside His design, stop asking for a blessing and start asking for mercy to do the hard thing. Cut it off. Pluck it out. Better to enter life maimed than to keep the whole body and be cast into hell. That is not harshness but the surgery of a Father who loves you.
Then, when you have obeyed, the peace will come. Not the peace of a quieted conscience while sin remains, but the deep, unshakable peace of a conscience washed clean. That is the rest where sorrow and sighing flee away. That is the light no darkness can overcome. Christ enables; He upholds; but He does not spare us the fight. The labor of virtue is real, yet it is a light yoke compared to the crushing weight of unrepented sin. Throw off that weight. Do it today. And you will find that the strength you begged for is already there, given in the very act of faith that steps out of the shadows and into the burning, beautiful light.