Where is the crisis?
Has the art changed in 18 months, have you changed, or has something outside you changed (not in the dojo)?
At this point in my life, I am struggling with myself while I run a buiness. [the usual business worries; money in, out, who owes me, who do I owe and so forth] and haven't been on the mat for too many months.
Perhaps the novelty of the art has worn off? As a refresher, I once went to a seminar (Just one session, I thought) and what I saw was refreshing. And that helped me continue in the art. For to train in similar techniques with the same group of people can feel, well, not so fresh after a while.
So maybe visit another dojo. maybe aikido, maybe not. Maybe visit on the mats, maybe just watch.
If in doubt, do something. If it doesn't work, do something else. Sometimes, do nothing is also doing something.
(all very weird, and zen like, but meant with all heart!