I am terrified that all the worship I have done my whole life might be secretly worthless in Allah’s sight. How do I live with that fear?
That fear is not a sign that something has gone wrong inside you. A man who does not care never lies awake wondering whether his worship was accepted. It is the one who is genuinely trying who cannot rest. So start from there: the ache tells you something is alive.
The Qur’an describes the servants Allah praises, and the description may surprise you.
“And those who give what they give while their hearts are fearful.”
Qur’an, Al-Mu’minun 23:60 · meaning
The Prophet, peace be upon him, explained this verse himself. When Aisha, may Allah be pleased with her, asked whether these fearful ones were people who steal and sin, he told her no: they are people who pray, and fast, and give in charity, and still fear that it may not be accepted from them. The trembling heart in the verse is not the sinner’s heart. It is the worshipper’s.
“No, O daughter of As-Siddiq. Rather, they are those who fast and pray and give charity, while they fear that it will not be accepted from them.”
The Prophet (peace be upon him), Jami’ at-Tirmidhi (3175) · meaning
So the fear you took as evidence against you is the Prophet’s own description of the sincere. But fear was never meant to turn into despair, and Allah has drawn that line Himself.
“O My servants who have transgressed against themselves, do not despair of the mercy of Allah. Indeed, Allah forgives all sins.”
Qur’an, Az-Zumar 39:53 · meaning
Hold the two together. The fear keeps you humble and keeps you working; the hope keeps you from sinking. Worship offered with a trembling but hopeful heart is exactly the worship Allah loves, and He is far too generous to turn away a servant who kept coming to His door his whole life. Do your small deeds with care and leave the accepting to Him. That is not carelessness, it is trust.
One small step: After each prayer today, say once: “O Allah, accept it from me, and let me never despair of Your mercy.”