The prayer was not casual. That is what makes this so hard to file away. You were not going through the motions — you begged, at some point, in a car or a bathroom or on a floor, in the most honest language you have ever used with God. And then the thing you begged about happened anyway, sometimes within hours. There is no way to be in that sequence without it meaning something, and every meaning available seems to be bad.
The options arrive fast. God did not hear. God heard and declined. God is real but has moved on from you specifically. Or the one that does the most damage: God would have, if your faith had been the right size. That last one is the one people are handed most often, usually by someone who means well, and it lands like a diagnosis.
Then there is the sheer double exposure of it. A person without faith who relapses has one problem. You have that problem plus a spiritual one layered on top, and the two feed each other. The shame from the using makes you avoid God, and avoiding God makes the next relapse more likely, and the next relapse makes the shame worse. It is a closed loop and it runs on its own once it starts.
And you probably cannot say any of this where you worship. The honest sentence — I prayed and I used and I do not know what to do with that — sounds like a crisis of faith to people who have not been here, so it stays unsaid, and you keep going to church and singing the songs with a question in your chest that nobody in the building knows about.
What almost nobody says plainly is this: nothing in scripture promises that sincere prayer removes a physical dependency on request. That promise was made to you by people, not by the text. And when the promise broke, you assumed the fault was in you rather than in the promise.