Sometimes, the best thing to do is to hang tight. Not to give up on your ability to move forward, but to acknowledge that you are not doing anything wrong, that you are in fact doing many things right, and to breathe and let go and stop fighting.
In the boat, that doesn't always mean that things feel better or move better, not right away. But deciding that you're not going to do whatever it takes to hold the boat up, or try to fix with your own recovery what the person in front of you or behind you is doing--the boat flops, it lurches, and maybe a stroke for a seat or two is rendered ineffective--and then, it relaxes. Unfortunately, if you and your boatmates don't take that as an opportunity to maintain the change, it becomes a cycle: maybe lasting a piece, maybe a practice, maybe a week.
It's incredibly frustrating to feel like you know what you're doing, to see in other boats that you actually do know what you're doing, but in the boat where it matters, to feel lost. This same feeling of powerlessness can be anywhere--not just in practice, but maybe in a class where a teacher doesn't seem to like your work, or a relationship that you care very much about but cannot steer, or trying to maneuver future plans while facing several unknowns and the plans of others. The ability to mindfully let go of the fear, the unknown, the shitty stuff you can't control, and to keep putting your blade in as best you can and working hard on the drive (so to speak)...is perhaps one of the most important things in getting things to turn out all right in the end.