Entering the dip.

The Dip is the long slog between starting and mastery. A long slog that’s actually a shortcut, because it gets you where you want to go faster than any other path.
~ Seth Godin, The Dip: A Little Book That Teaches You When to Quit (and When to Stick)

First, it's difficult to figure out for ourselves that we have entered the dip. Because the dip wants us to just leave the project and do something else. It makes us feel miserable and question whatever we know.

Secondly, it's an indicator that we are making progress, that we are moving forward, that we are on the right track. That whatever we have been doing is actually working.

And finally, the dip is not measured in weeks, it's measured in iterations. If your plan is to wait out the dip, then you are going to remain there for a long time. On the other hand, if you get in your reps and figure out a way to move forward without worrying about immediate outcomes, you are more likely to come out on the other side sooner rather than later.