If you're functioning okay, therapy should be tried before medication. Even if you're on medication, you should try therapy if you ever want to stop taking it. The difference is, medication tamps down symptoms but doesn't tackle the cause, whereas if therapy works, you're cured. But it might not be quick and it might take a few tries before you find the right therapist. And there's never a guarantee with either drugs or therapy that it will work. You'll find out soon enough if it's a good substitute or not, but even if it isn't it's a good idea.
Therapy is excellent. I'm not sure if it is a substitute, per say but if you don't need medication anymore, a therapist helps you with coping skills and to get to the root of the problem. Sometimes people take themselves off medication and find that they do need it again and don't be upset if that happens. It's actually quite common. good luck