Have you questioned your dx? A lot (probably the majority) of people who are dx with bipolar disorder started out with major depression, ongoing or recurring for years in most cases. I was on only antidepressants (off and on, mostly on) for about 8 years before I was dx with bipolar 2. I lean toward the depressed side much more as well, and although my pdoc wanted me to go off antidepressants once I was stable on my mood stabilizer (Lamictal), I told him that I'm much more likely to get depressed than hypomanic and although the hypomania is very uncomfortable, the depression is much worse.

Trazadone has really helped with my sleep, which is super important--if my sleep schedule gets off even a little, I'm headed for trouble.