How do you stop (without medication) constant anxious/obsessive thoughts?

Acceptance: Trying to stop thoughts can actually lead to "thought-rebounding" or even more of the unwanted thoughts. Problem-solving, acceptance, and cognitive restructuring are behaviors that can help reduce anxiety. How about labeling these thoughts as "boring" and following your curiosity? Seeing a therapist is recommended if you want professional help. You might also try a book with good suggestions.

Psychotherapy: Ask yourself what environmental and interpersonal stressors you face during your waking hours, and whether or not you find yourself obsessing about them at night, which could be resulting in sleep loss. Consider going to a reputable psychotherapist for stress management therapy, and exploration of non-biochemical sources of anxiety.