Was told i may have postnatal depression. what can i try first besides antidepressants?

Psychotherapy: Please consider seeing a psychologist or other therapist for psychotherapy. It can have excellent results in all kinds of depression, including post-partum. If sessions don't seem to help within a reasonable time, then you can consider antidepressant therapy -- a psychiatrist can help you with that. Make sure you're taking at least 1-2 g/day of epa in fish oil, too. Getting enough sleep, etc.