Taking antidepressants and getting the manic reaction is certainly a faster way to the bipolar diagnosis train, but it's likely you don't want it to go that way. Do try adjusting your eating and exercise if you know they're far off what they should be. If you eat reasonably well, though, and are active enough, consider pestering them. Or find things in your history that might be more manic than you think. Psychiatry is quirky in that, except for extreme cases, their diagnosis is based entirely on what you tell them. Sometimes you need to know more about what you're describing than you could ever reasonably be expected to pay attention to.
Eat better, exercise, get some sun, work on redirecting your thoughts regularly (deliberately interrupt a down train of thought, break it down, figure out why it's there, challenge it, reverse it, etc -- it's loopy the first few weeks, but it gets to feeling more natural, and being more effective, the longer you do it), and check back in with the docs if nothing is changing. Medicine should be a last resort, but it shouldn't take until you feel it's your only option other than suicide before you get it. If you suspect bipolar, keep a mood journal. Bipolars react to some really wacky foods, so it would be helpful to keep track of what you eat, too.
Pay attention to the weather. There could be a touch of Seasonal Affective Disorder in there, too, in which case my suggestion amounts to "move away from a place where it's dark and dreary 90% of the year."
