Struggling with Fallibilism and Yaqīn: Can I Be Muslim Without Absolute Certainty?

As-salām alaykum, I’ve been in a religious crisis for about six months and I’m hoping someone can help with some doubts. I’m a medical student and this all began during my psychiatry rotation on a ward for young people having first psychotic episodes. Many were my age. While some were clearly very unwell, others seemed fine outwardly - friendly, social, the kind of people you wouldn’t suspect of psychosis unless you talked to them deeply. In those conversations they described experiences like being watched, followed, or poisoned. To them, those experiences are 100% real. They have memories and sensory impressions (images, sounds, touches) that confirm the delusions. Trying to convince them they’re wrong feels pointless because they have direct lived evidence for their beliefs. That made me ask: how do we know what’s true? How can we be confident about what’s real and what’s not? Most of our knowledge depends on senses and reason, but those can err. It seemed to me that if senses and reasoning aren’t infallible, we can’t be 100% certain about anything. I went through a Cartesian-style crisis and looked for Islamic answers. I read al-Ghazālī’s al-Munqidh min al-Ḍalāl and found comfort that a great scholar had similar struggles. He wrote that his cure was not a philosophical proof but a light God cast into his breast. I’ve offered tahajjud, fasted voluntarily, and made sincere duʿāʾ, but I haven’t felt that same ‘light’ yet. The worry that our experiences are fallible keeps returning. I then read an article on Ibn Taymiyyah’s critique of radical skepticism which convinced me that extreme skepticism - doubting everything including your own existence - is unliveable. If you doubt every bit of experience or the logic you use to doubt, you can’t act. But not all skepticism is radical. Fallibilism (a term from modern philosophy) accepts that human knowledge may be mistaken while still allowing us to act on the best available evidence. A fallibilist trusts well-supported medicine while admitting it might fail. That position feels honest to me. Some writers say belief in God rests on fitrah and doesn’t need philosophical proof; placing God at the foundation removes many skeptical doubts because a perfect Creator wouldn’t be a deceiver, so our faculties are generally trustworthy. I find that appealing, but it doesn’t fully resolve my tension with fallibilism. Fallibilists aren’t radical skeptics - we simply accept that certainty in the absolute sense may be impossible. To restate my stance: I think human knowledge is never 100% certain and is always open to error. Still, we should act on the best-supported evidence while being aware of that fallibility. My struggle is: how does that fit with being Muslim? Even if the evidence for Islam feels strong to me, fallibilism suggests absolute certainty is unattainable. Islam often speaks of yaqīn - not merely confidence but certainty. Does yaqīn demand epistemic certainty that rules out any possibility of error? Or can yaqīn be understood as firm trust and commitment even while acknowledging human fallibility? This matters practically: can I sincerely make duʿāʾ, rely on Allāh, fear accountability, and seek His mercy if I cannot claim absolute certainty of His existence? Would I be merely “acting as if”? I want to know whether Islam can accommodate a fallibilist stance or whether genuine faith requires a kind of certainty I can’t honestly assert. I’d appreciate thoughtful replies, especially from those familiar with yaqīn, fitrah, or Islamic approaches to knowledge.