One of the honest questions people have about prayer is whether asking repeatedly shows a lack of faith. If I really believed, would I only need to ask once?
Jesus taught persistence as the normal shape of prayer. Asking again is not unbelief, but notice whether you leave lighter than you came.
Jesus answered that with a story. Luke 18 opens by saying he spoke a parable to this end, that men ought always to pray and not to faint. Then he tells about a widow who keeps coming to an unjust judge until he acts, simply because she will not stop.
The point is not that God is reluctant like that judge. The point is the opposite, an argument from lesser to greater. If persistence moves even a corrupt official, how much more will it be met by a good Father.
So persistence is not unbelief. Jesus taught it as the normal shape of prayer.
But there is a difference between persistence and anxiety, and it is worth learning to feel it.
Persistence keeps bringing the same request and leaves it with God each time. Anxiety keeps bringing the same request and picks it back up on the way out.
One of the practical tests is what happens after you pray. If you get up lighter, even with nothing resolved, that was probably faith. If you get up carrying more than you sat down with, you were rehearsing, not praying.
1 Thessalonians 5:17 says pray without ceasing. That is not a command to never stop talking. It is a description of a life lived with the line open, returning to the same matters as often as they come to mind, and each time handing them over again.
Keep asking. That is allowed. That was the instruction.