Re: aikido crisis. :(
Nathan says it right, keep going to the dojo. It's the only way to get off the plateau.
Find something else to do if you want to, but know that sooner or later the plateau will show up there too. You have the opportunity to choose right now how you will live your life: finding a new interest every other year -or- walking the path to mastery.
Mastery in aikido is not better or worse than mastery of anything else though. Try table tennis, operating heavy machinery or something else if you want to. Just be aware that it's when you arrive at the plateau that you will have to make the choice, not in the beginning when you are enthusiastic about whatever it is you do.